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Speaker
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Transcript
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Hello. |
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My name is Ron Kenett. This |
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is a joint talk with Chris |
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Gotwalt and we basically |
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have two messages |
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that should come out of the |
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talk. One is that we should |
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really be concerned about |
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information and information |
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quality. People tend to talk |
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about data and data quality, but |
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data is really not the the issue. |
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We are statisticians. We are |
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data scientists. We turn numbers, |
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data into information so that |
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our goal should be to make sure |
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that we generate high quality |
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information. The other message |
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is that JMP can help you |
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achieve that, and this is |
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actually turning out to be in |
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surprising ways. So by combining |
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the expertise of Chris and an |
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introduction to information |
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quality, we hope that these two |
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messages will come across |
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clearly. So if I had to |
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summarize what it is that we |
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want to talk about, after all, |
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it is all about information |
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quality. I gave a talk at |
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at the Summit in Prague four years |
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ago and that talk was generic. |
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It talked about moving the |
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journey from quality by design. |
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My journey doing information |
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quality. In this talk we focus |
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on how this can be done with |
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JMP. This is a more detailed |
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and technical talk than the |
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general talk I gave in Prague. |
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You can watch that talk. |
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There's a link listed here. You can |
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find it on the JMP community. |
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So we're going to talk about |
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information quality, which is |
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the potential of the data set, a |
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specific data set, to achieve a |
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particular goal, a specific goal, |
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with the given empirical method. |
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So in that definition we have |
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three components that are |
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listed. One is a certain data |
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set. Here is the data. The |
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second one is the goal, |
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the goal of the analysis, what |
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it is that we want to achieve. |
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And the third one is how we will |
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do that, which is, with what |
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methods we're going to generate |
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information, and that potential |
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is going to be assessed with the |
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utility function. And I will |
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begin with an introduction to |
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information quality, and then |
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Chris will will take over, |
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discuss the case study and and |
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show you how to conduct an |
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information quality assessment. |
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Eventually this should |
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answer the question how JMP |
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supports InfoQ, that |
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would be the the bullet points |
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that you can...the take away points |
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from the talk. The setup for |
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this is that we we encourage |
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what I called a lifecycle view |
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of statistics. In other words, |
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not just data analysis. |
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We should know...we should be part |
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of the problem elicitation |
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phase. Also, the goal |
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formulation phase, that deserves |
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a discussion. We should |
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obviously be involved in the |
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data collection scheme if it's |
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through experiments or through |
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surveys or through observational |
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data. Then we should also take |
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time for formulation of the |
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findings and not just pull out |
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printed reports on on |
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regression coefficients |
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estimates and and their |
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significance, but we should |
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also discuss what are the |
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findings? Operationalization of |
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findings meaning, OK, what can we |
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do with these findings? What are |
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the implications of the |
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findings? This should should... |
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needs to be communicated to the |
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right people in the right way, |
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and eventually we should do an |
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impact assessment to figure out, |
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OK, we did all this; what has |
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been the added value of our |
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work? I talked about the life |
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cycle of your statistics a few years |
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ago. This is the prerequisite, |
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the perspective to what |
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I'm going to talk about. So as I |
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mentioned, the information |
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quality is the potential of a |
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particular data set to achieve a |
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particular goal using given |
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empirical analysis methods. This |
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is identified through four |
| components |
the goal, the data, |
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the analysis method, and the |
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utility measure. So in a in a |
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mathematical expression, the |
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utility of applying f to x, |
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condition on the goal, is how we |
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identify InfoQ, information |
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quality. This was published in |
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the Royal Statistical Society |
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Series A in 2013 with eight |
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discussants, so it was amply |
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discussed. Some people thought |
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this was fantastic and some |
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people had a lot of critique on |
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that idea, so this is a wider |
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scope consideration of what |
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statistics is about. We also |
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wrote in 2006, we meeting myself |
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and Galit Shmueli, a book called |
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Information Quality. And in |
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the context of information |
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quality we did what is called |
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deconstruction. David Hand has |
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a paper called Deconstruction |
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of Statistics. This is the |
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deconstruction of information |
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quality into eight dimensions. I |
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will cover these eight dimensions. |
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That's my part in the talk and |
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then Chris will show how this |
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is implemented in a specific |
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case study. |
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Another aspect that relates to |
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this is another book I have. |
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This is recent, a year ago |
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titled The Real Work of Data |
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Science and we talk about what |
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is the role of the data |
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scientists in organizations and |
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in that context, we emphasized |
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the need for the data scientist |
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to be involved in the generation |
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of information as an...information |
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quality as meeting the goals of |
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the organization. So let me |
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cover the eight dimensions. That's |
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that's that's my intro. The |
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first one is data resolution. We |
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have a goal. OK, we we would |
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like to know the level of flu |
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because in the country or in the |
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area where we live, because that |
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will impact our decision on |
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whether to go to the park where |
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we could meet people or going to |
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a...to a jazz concert. And that |
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concert is tomorrow. |
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If we look up the CDC data on |
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the level of flu, that data is |
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updated weekly, so we could get |
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the red line in the graph you |
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have in front of you, so we |
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could get data of a few days |
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ago, maybe good, maybe not good |
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enough for our gold. Google Flu, |
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which is based on searches |
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related to flu, is updated |
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momentarily, so it's updated |
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online, it will probably give |
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us better information. So for |
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our goal, the blue line, the |
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Google trend...the Google Flu |
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Trends indicator, is probably |
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more appropriate. The second |
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dimension is data structure. |
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To meet our goal, we're going to |
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look at data. We should...we |
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should identify the data sources |
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and the structure in these data |
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sources. So some data could be |
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text, some could be video, some |
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could be, for example, the |
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network of recommendations. This |
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is an Amazon picture on how if |
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you look at the book, you're |
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going to get some |
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other books recommended. And if |
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you go to these other books, |
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you're going to have more data |
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recommended. So the data |
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structure can come in all sorts |
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of shapes and forms and this can |
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be text. This can be functional |
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data. This can be images. We are |
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not confined now to what we used |
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to call data, which is what you |
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find in an Excel spreadsheet. |
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The data could be corrupted, |
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could have missing values, could |
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have unusual patterns which |
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which would be |
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something to look into. Some |
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patterns, where things are |
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repeated. Maybe some of the data |
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is is just copy and paste and we |
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would like to be warned about |
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such options. The third |
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dimension is data integration. |
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When we consider the data from |
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these different sources, we're |
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going to integrate them so we |
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can do some analysis linkage |
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through an ID. For example, we |
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would do that, but in doing that, |
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we might create some issues, for |
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example, in in disclosing data |
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that normally should be |
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anonymized. Data |
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integration, yeah, that will |
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allow us to do fantastic things, |
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but if the data is perceived to |
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have some privacy exposure |
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issues, then maybe the quality |
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of the information from the |
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analysis that we're going to do |
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is going is going to be |
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affected. So data integration |
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should be looked into very, very |
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carefully. This is what people |
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likely used to call ETL |
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extract, transform and load. We |
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now have much better methods for |
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doing that. The join option, for |
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example, in JMP will offer |
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options for for doing that. |
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Temporal relevance. OK, that's |
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pretty clear. We have data. It is |
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stamped somehow. If we're going |
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to do the analysis later, later |
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after the data collection, and |
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if the deployement that we |
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consider is even later, then the |
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data might not be temporally |
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relevant. In a common |
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situation, if we want to compare |
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what is going on now, we would |
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like to be able to make this |
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comparison to recent data or |
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data before the pandemic |
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started, but not 10 years |
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earlier. The official statistics |
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on health records used to be two |
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or three years behind in terms |
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of timing, which made it very |
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difficult the use of official |
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statistics in assessing |
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what is going on with the |
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pandemic. Chronology of data and |
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goal is related to the decision |
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that we make as a result of our |
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goal. So if, for example, our |
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goal is to forecast air quality, |
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we're going to use some |
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predictive models on the Air |
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Quality Index reported on a |
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daily basis. This gives us a one |
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to six scale from hazardous to |
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good. There are some values |
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which are representing levels of |
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health concern. Zero-50 is good; |
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300-500 is hazardous and the |
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chronology of data and goal |
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means that we should be able to |
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make a forecast on a daily |
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basis. So the methods we use |
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should be updated on a daily |
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basis. If, on the other hand, |
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our goal is to figure out how is |
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this AQI index computed, then we |
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are not really bound by the the |
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the timeliness of the analysis. |
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You know, we could take our |
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time. There's no urgency in |
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getting the analysis done on a |
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daily basis. Generalizability, |
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the sixth dimension, is about |
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taking our findings and |
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considering where this could |
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apply in more general terms, |
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other populations, all |
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situations. This can be done |
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intuitively. Marketing managers who |
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have seen a study on the on the |
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market, let's call it A, might |
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already understand what are the |
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implications to Market B |
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without data. People who are |
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physicists will be able to |
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make predictions based on |
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mechanics on first principles |
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without without data. |
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So some of the generalizability |
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is done with data. This is the |
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basis of statistical |
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generalization, where we go from |
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the sample to the population. |
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Statistical inferences is about |
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generalization. We generalize |
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from the sample to the |
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population. And some can be |
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domain based, in other words, |
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using expert knowledge, domain |
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expertise, not necessarily with |
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data. We have to recognize that |
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generalizability is not just |
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done with statistics. |
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The seventh dimension is |
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construct operationalization, |
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which is really about what it is |
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that we measure. We want to |
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assess behavior, emotions, what |
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it is that we can measure, that |
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will give us data that reflects |
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behavior or emotions. |
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The example I give here |
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typically is pain. |
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We know what is pain. How do |
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we measure that? If you go to a |
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hospital and you ask the nurse, |
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how do you assess pain, they |
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will tell you, we have a scale, |
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1 to 10. It's very |
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qualitative, not very |
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scientific, I would say. If we |
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want to measure the level of |
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alcohol in drivers on the...on |
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the road, it will be difficult to |
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measure. So we might measure |
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speed as a surrogate measure. |
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Another part of |
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operationalization is the other |
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end of the story. In other |
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words, the first part, the |
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construct is what we measure, |
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which reflects our goal. The the |
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end...the end result here is that |
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we have findings and we want to |
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do something with them. We want |
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to operationalize our finding. |
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This is what the action |
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operationalization is about. |
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It's about what you do with the |
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findings and then being |
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presented here on a podium. We |
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used to ask three questions. |
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These are very important |
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questions to ask. Once you have |
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done some analysis, you have |
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someone in front of you who |
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says, oh, thank you very much, |
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you're done...you, the statistician |
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or the data scientist. So this |
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this takes you one extra step, |
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getting you to ask your customer |
| these simple questions |
What do |
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you want to accomplish? How will |
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you do that and how will you |
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know if you have accomplished |
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that? We we can help answer, or |
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at least support, some of these |
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questions we've answered. |
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The eighth dimension is |
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communication. I'm giving you an |
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example from a very famous old |
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map from the 19th century, which |
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is showing the march of the |
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Napoleon Army from France to |
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Moscow to Russia. You see the |
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numbers are the the width of |
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the path indicates the size |
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of the army, and then on on in |
| |
black you see what happened to |
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them on their on their way back. |
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So basically this was a |
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disastrous march. We we we we |
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can relate this old map to |
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existing maps, and there is a |
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JMP add-in, which you can |
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find on the JMP Community, to to |
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show you with bubble plots, |
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dynamic bubble plots what this |
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looks like. So I I've covered |
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very quickly the eight information |
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quality dimensions. My last |
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slide is that what I've talked |
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about from a historical |
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perspective, really put some |
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proportions to what I'm saying. |
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I think we are really in the era |
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of information quality. We used |
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to be concerned with product |
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quality in the 18th century, the |
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17th century. We then moved to |
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process quality and service |
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quality. This is a short memo |
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on proposing a control chart, |
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1924, I think. |
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Then we move to management |
| |
quality. This is the Juran |
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trilogy of design, improvement |
| |
and control. Six Sigma (define, |
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measure, analyze, improve) |
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control process is the |
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improvement process of Juran, |
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and Juran was the grand father |
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of Six Sigma in that sense. |
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Then in the '80s, Taguchi came |
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in. He talks about robust |
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design. How can we handle |
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variability in inputs by proper |
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design decisions? And now we are |
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in the Age of information |
| |
quality. We have sensors. We |
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have flexible systems. We are |
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depending on AI and machine |
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learning and data mining and we |
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are gathering big big big |
| |
numbers, but which we call big |
| |
data. The interest in information |
| |
quality should be a prime prime |
| |
interest. I'm going to try and |
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convince you of, with the help |
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of Chris, that. |
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We are here and JMP can |
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help us achieve that in in a |
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really unusual way. |
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What you will see at the end of |
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the case study that Chris will |
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show is also how to do it an |
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information quality assessment and |
| |
on a specific study, basically |
| |
generate an information quality |
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score. So if we go top down, I |
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can tell you this study, this |
| |
work, this analysis is maybe 80% or |
| |
maybe 30% or maybe 95%. |
| |
And through the example you will |
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see how to do that. There is a |
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JMP add-in to provide this |
| |
assessment. It's it's actually |
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quite quite easy. There's |
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nothing really sophisticated |
| |
about that. So I'm done and |
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Chris, after you. Thanks, Ron. So |
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now I'm going to go through the |
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analysis of a data set in a way |
| |
that explicitly calls out the |
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various aspects of information |
| |
quality and show how JMP can be |
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used to assess an improvement |
| |
for InfoQ. So first off, I'm |
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going to go through the InfoQ |
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components. The first InfoQ |
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component is the goal, so in |
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this case the problem statement |
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was that a chemical company |
| |
wanted a formulation that |
| |
maximized product yield while |
| |
minimizing a nuisance impurity |
| |
that resulted from the reaction. |
| |
So that was the high level goal. |
| |
In statistical terms, we wanted |
| |
to find a model that accurately |
| |
predicted a response on a data |
| |
set so that we could find a |
| |
combination of ingredients and |
| |
processing steps that would lead |
| |
to a better product. |
| |
The data are set up in 100 |
| |
experimental formulations with |
| |
one primary ingredient, X1,and |
| |
10 additives. There's also a |
| |
processing factor in 13 |
| |
responses. The data are |
| |
completely fabricated but were |
| |
simulated to illustrate the same |
| |
strengths and weaknesses of the |
| |
original data. The data |
| |
formulation was made was also |
| |
recorded. We will be looking at |
| |
this data closely, so I want to |
| |
elaborate beyond pointing out |
| |
that they were collected in an |
| |
ad hoc way, changing one or two |
| |
additives at a time rather than |
| |
as a designed or randomized |
| |
experiment. There's a lot of |
| |
ways to analyze this data, the |
| |
most typical being least |
| |
squares modeling with forward |
| |
selection on selected responses. |
| |
That was my original intention |
| |
for this talk, but when I showed |
| |
the data to Ron, he immediately |
| |
recognized the response columns |
| |
as time series from analytical |
| |
chemistry. Even though the data |
| |
were simulated, he could see the |
| |
structure. He could see things |
| |
in the data that I didn't see |
| |
and read into it wasn't. I found |
| |
this to be strikingly |
| |
impressive. It's beyond the |
| |
scope of this talk, but there is |
| |
an even better approach based on |
| |
ensemble modeling using |
| |
fractionally weighted |
| |
bootstrapping. Phil Ramsey, |
| |
Wayne Levin and I have another |
| |
talk about this methodology at |
| |
the European Discovery |
| |
Conference this year. The |
| |
approach is promising because it |
| |
can fit models to data with |
| |
more active interactions than |
| |
there are runs. The fourth and final |
| |
component of information quality |
| |
is utility, which is how well we |
| |
are able to assess our goals. Or |
| |
how do we measure how well we've |
| |
assessed our goals? There's a |
| |
domain aspect which is in this |
| |
case we want to have a |
| |
formulation that leads to |
| |
maximized yields and minimized the |
| |
waste in post processing of the |
| |
material. The statistical |
| |
analysis utility refers to the |
| |
model that we fit. What we're |
| |
going for there is least |
| |
squares accuracy of our model in |
| |
terms of how well we're able to |
| |
predict what the...what would |
| |
result from candidate |
| |
combinations of formulation...of |
| |
mixture factors. Now I'm going |
| |
to go through a set of questions |
| |
that make up a detailed InfoQ |
| |
assessment as organized into the |
| |
eight dimensions of information |
| |
quality. I want to point out |
| |
that not all questions will be |
| |
equally relevant to different |
| |
data science and statistical |
| |
projects, and that this is not |
| |
intended to be rigid dogma but |
| |
rather a set of things that are |
| |
a good idea to ask oneself. |
| |
These questions represent a kind |
| |
of data analytic wisdom that |
| |
looks more broadly than just the |
| |
application of a particular |
| |
statistical technology. A copy |
| |
of a spreadsheet with these |
| |
questions along with pointers to |
| |
JMP features that are the most |
| |
useful for answering a |
| |
particular one will be uploaded |
| |
to the JMP Community along |
| |
with this talk for you to use. As |
| |
I proceed through the questions, |
| |
I'll be demoing an analysis of |
| |
the data in JMP. So Question 1 |
| is |
is the data scale used |
| |
aligned with the stated goal? So |
| |
the Xs that we have consist of |
| |
a single categorical variable |
| |
processing and the 11 continuous |
| |
inputs. These are measured |
| |
as percentages and are also |
| |
recorded to half a percent. We |
| |
don't have the total amounts of |
| |
the ingredients, only the |
| |
percentages. The totals are |
| |
information that was either lost |
| |
or never recorded. There are |
| |
other potentially important |
| |
pieces of information that are |
| |
missing here. The time between |
| |
formulating the batches and |
| |
taking the measurements is gone |
| |
and there could have been other |
| |
covariate level information that |
| |
is missing here that would have |
| |
described the conditions under |
| |
which the reaction occurred. |
| |
Without more information than I |
| |
have, I cannot say how important |
| |
this kind of covariate information |
| |
would have been. We do have |
| |
information on the day of the |
| |
batch, so that could be used as |
| |
a surrogate possibly. Overall we |
| |
have what are, hopefully, the most |
| |
important inputs, as well as |
| |
measurements of the responses we |
| |
wish to optimize. We could have |
| |
had more information, but this |
| |
looks promising enough to try |
| |
and analysis with. The second |
| |
question related to data |
| |
resolution is how reliable and |
| |
precise are the measuring devices |
| |
and data sources. And the fact |
| |
is, we don't have a lot of |
| |
specific information here. The |
| |
statistician internal the |
| |
company would have had more |
| |
information. In this case we |
| |
have no choice but to trust that |
| |
the chemists formulated and |
| |
recorded the mixtures well. The |
| |
third question relative to data |
| resolution is |
is the data |
| |
analysis suitable for the data |
| |
aggregation level? And the |
| |
answer here is yes, assuming |
| |
that their measurement system is |
| |
accurate and that the data are |
| |
clean enough. What we're going |
| |
to end up doing actually is |
| |
we're going to use the |
| |
Functional Data Explorer to |
| |
extract functional principal |
| |
components, which are a data |
| |
derived kind of data |
| |
aggregation. And then we're |
| |
going to be modeling those |
| |
functional principal components |
| |
using the input variables. So |
| |
now we move on to the data |
| |
structure dimension and the |
| |
first question we ask is, is the |
| |
data used aligned with the |
| |
stated goal? And I think the |
| |
answer is a clear yes here. We're |
| |
trying to maximize |
| |
yield. We've got measurements for |
| |
that, and the inputs are |
| |
recorded as Xs. The second data |
| |
structure question is where |
| |
things really start to get |
| |
interesting for me. So this is |
| |
are the integrity details |
| |
(outliers, missing values, data |
| |
corruption) issues described and |
| |
handled appropriately? So from |
| |
here we can use JMP to be able |
| |
to understand where the outliers |
| |
are, figure out strategies for |
| |
what to do about missing values, |
| |
observe their patterns and so |
| |
on. So this is this is where |
| |
things are going to get a little |
| |
bit more interesting. The first |
| |
thing we're going to do is we're |
| |
going to determine if there are |
| |
any outliers in the data that we |
| |
need to be concerned about. So |
| |
to do that, we're going to go |
| |
into the explore outliers |
| |
platform off of the screening |
| |
menu. We're going to load up the |
| |
response variables, and because |
| |
this is a multivariate setting, |
| |
we're going to use a new feature |
| |
in JMP Pro 16 called Robust |
| |
PCA Outliers. So we see where |
| |
the large residuals are in those |
| |
kind of Pareto type plots. |
| |
There's a snapshot showing where |
| |
there's some potentially |
| |
unusually large observations. I |
| |
don't really think this looks |
| |
too unusual or worrisome to me. |
| |
We can save the large outliers |
| |
to a data table and then look at |
| |
them in the distribution |
| |
platform and what we see kind of |
| |
looks like a normal distribution |
| |
with the middle taken out. So I |
| |
think this is data that are |
| |
coming from sort of the same |
| |
population and there's nothing |
| |
really to worry about here, |
| |
outliers-wise. So once we've |
| |
taken care of the outlier |
| |
situation we go in and explore |
| |
missing values. So what we're |
| |
going to do first is we're going |
| |
to load up the Ys as...into the |
| |
platform, and then we're going |
| |
to use the missing value |
| |
snapshot to see what patterns |
| |
they are amongst our missing |
| |
values. It looks like the |
| |
missing values tend to occur in |
| |
horizontal clusters, and there's |
| |
also the same missing values |
| |
across rows. So you can see that |
| |
with the black splotches here. |
| |
And then we'll go apply an |
| |
automated data imputation, |
| |
which goes ahead and saves |
| |
formula columns that impute |
| |
missing values in the new |
| |
columns using a regression type |
| |
algorithm that was developed by |
| |
a PhD student of mine named Milo |
| |
Page at NC State. So we can play |
| |
around a little bit and get a |
| |
sense of like how the ADI |
| |
algorithm is working. So it's |
| |
created these formula columns |
| |
that are peeling off elements of |
| |
the ADI impute column, which is |
| |
a vector formula column, and the |
| |
scoring impute function |
| |
is calculating the expected |
| |
value of the missing cells given |
| |
the non missing cells, whenever |
| |
it's got a missing value. And it's |
| |
just carrying through a non |
| |
missing value. So you can see 207 |
| |
in YO...Y6 there. It's initially |
| |
207 but then I change it to |
| |
missing and it's now being |
| |
imputed to be 234. |
| |
So I'll do this a couple of times so |
| |
you can kind of see how how it's |
| |
working. So here I'll put in a big |
| |
value for Y7 and that's now. |
| |
been replaced. And if we go down |
| |
and we add a row, |
| |
then all missing values are there |
| |
initially and the column means |
| |
are replaced for the |
| |
imputations. If I were to go |
| |
ahead and add values for some of |
| |
those missing cells, it would |
| |
start doing the conditional |
| |
expectation of the still missing |
| |
cells using the information |
| |
that's in the missing one....the |
| |
non missing ones. So our next |
| |
question on data structure is |
| |
are the analysis methods |
| |
suitable for the data structure? |
| |
So we've got 11 mixture inputs |
| |
and a processing variable that's |
| |
categorical. Those are going |
| |
to be inputs into a least |
| |
squares type model. We have |
| |
13 continuous responses and |
| |
we can model them using... |
| |
individually using least |
| |
squares. Or we can model |
| |
functional principal |
| |
components. The...now there are |
| |
problems. The Xs are...the |
| |
input variables have not been |
| |
randomized at all. It's very |
| |
clear that they would muck |
| |
around with one or more of |
| |
the compounds and then move |
| |
on to another one. So the |
| |
order in which the |
| |
the input variables were varied |
| |
was kind of haphazard. It's a |
| |
clear lack of randomization, and |
| |
that's going to negatively |
| |
impact our...the generalizability |
| |
and strength of our conclusions. |
| |
Data integration is the third |
| |
InfoQ dimension. These data |
| |
are manually entered lab notes |
| |
consisting mostly of mixture |
| |
percentages and equipment |
| |
readouts. We can only assume |
| |
that the data were entered |
| |
correctly and that the Xs are |
| |
aligned properly with responses. |
| |
If that isn't the case, then the |
| |
model will have serious bias |
| |
problems and have |
| |
problems with generalizability. |
| |
Integration is more of an issue |
| |
with observational data |
| |
science problems in machine |
| |
learning exercises, than lab |
| |
experiments like this. Although |
| |
it doesn't apply here, I'll |
| |
point out that privacy and |
| |
confidentiality concerns can be |
| |
identified by modeling the |
| |
sensitive part of the data using |
| |
the to be published component |
| |
at the data. If the resulting |
| |
model is predicted, then one |
| |
should be concerned that privacy |
| |
concerns are not being met. Temporal |
| |
relevance refers to the |
| |
operational time sequencing of |
| |
data collection, analysis and |
| |
deployment and whether gaps |
| |
between those stages leads to a |
| |
decrease in the usefulness of |
| |
the information in the study. |
| |
In this case, we can only simply |
| |
hope that the material supplies |
| |
are reasonably consistent and |
| |
that the test equipment is |
| |
reasonably accurate, which is an |
| |
unverifiable assumption at this |
| |
point. The time resolution we |
| |
have when the data collection is |
| |
at the day level, which means |
| |
that there isn't much way that |
| |
we can verify if there is time |
| |
variation within each day. |
| |
Chronology of data and goal is |
| |
about the availability of |
| |
relevant variables both in terms |
| |
of whether the variable is |
| |
present at all in the data or |
| |
whether the right information |
| |
will be available when the model |
| |
is deployed. For predictive |
| |
models, this relates to models |
| |
being fit to data similar to |
| |
what will be present at the time |
| |
the model will be evaluated on |
| |
new data. In this way, our data |
| |
set is certainly fine. For |
| |
establishing causality, however, |
| |
we aren't in nearly as good a |
| |
shape because the lack of |
| |
randomization implies that time |
| |
effects and factor effects may |
| |
be confounded, leading to bias |
| |
in our estimates. Endogeneity, |
| |
or reverse causation, could |
| |
clearly be an issue here, as |
| |
variables like temperature and |
| |
reaction time could clearly be |
| |
impacting the responses, but have |
| |
been left unrecorded. Overall, |
| |
there is a lot we don't know |
| |
about this dimension in an |
| |
information quality sense. |
| |
The rest of the InfoQ |
| |
assessment is going to be |
| |
dependent upon the type of |
| |
analysis that we do. So at this |
| |
point I'm going to go ahead and |
| |
conduct an analysis of this data |
| |
using the Functional Data |
| |
Explorer platform in JMP Pro |
| |
that allows me to model across |
| |
all the columns simultaneously |
| |
in a way that's based on |
| |
functional principal components, |
| |
which contain the maximum amount |
| |
of information across all those |
| |
columns as represented in the |
| |
most efficient format possible. |
| |
I'm going to be working on the |
| |
imputed versions of the columns |
| |
that I calculated earlier in the |
| |
presentation. And I'm going to |
| |
point out that I'm going to be |
| |
working to find combinations of |
| |
the mixture factors that achieve |
| |
as closely as possible in a |
| |
least square sense, an ideal |
| |
curve that was created by the |
| |
practitioner that maximizes the |
| |
amount of potential product that |
| |
could be in a batch while |
| |
minimizing the amount of the |
| |
impurities that they |
| |
realistically thought a batch |
| |
could contain. So I begin the |
| |
analysis by going to the analyze |
| |
menu, bring up the Functional |
| |
Data Explorer. This has rows as |
| |
functions. I'm going to load up my |
| |
imputed rows, and then I'm going |
| |
to put in my formulation |
| |
components and my processing |
| |
column as a supplementary |
| |
variable. We've got an ID |
| |
function, that's batch ID. Here I |
| |
get in. I can see the functions, |
| |
both the overlay altogether, and |
| |
I can see the individual functions. |
| |
Then I can load up the target |
| |
function, which is the ideal. |
| |
And that will change the |
| |
analysis that results once I |
| |
start going into the modeling |
| |
steps. So these are pretty |
| |
simple functions, so I'm just |
| |
going to model them with |
| |
B splines. |
| |
And then I'm going to go into my |
| |
functional DOE analysis. |
| |
This is going to fit the model |
| |
that connects the inputs into |
| |
the functional principal |
| |
components and then connect all |
| |
the way through the |
| |
eigenfunctions to make it so |
| |
we're able to recover the |
| |
overall functions as they |
| |
changed, as we are varying the |
| |
mixture factors. The |
| |
functional principal component |
| |
analysis has indicated that |
| |
there are four dimensions of |
| |
variation in these response |
| |
functions. To understand what |
| |
they mean, let's go ahead and |
| |
explore with the FPC profiler. |
| |
So watch this pane right here as |
| |
I adjust FPC 1 and we can see |
| |
that this FPC is associated with |
| |
peak height. FPC2, it looks |
| |
like it's kind of a peak |
| |
narrowness. It's almost like a |
| |
resolution principal |
| |
component. The third one is |
| |
related to kind of a knee on |
| |
the left of the dominant peak. |
| |
And Peak 4 looks like it's |
| |
primarily related with the |
| |
impurity, so that's what the |
| |
underlying meaning is of |
| |
these four functional |
| |
principal components. |
| |
So we've characterized our goal |
| |
as maximizing the product and |
| |
minimizing the impurity, and |
| |
we've communicated that into the |
| |
analysis through this ideal or |
| |
golden curve that we supplied at |
| |
the beginning of the FDE |
| |
exercise we're doing. To get as |
| |
close as possible to that ideal |
| |
curve, we turn on desirability |
| |
functions. And then we can go |
| |
out and maximize desirability. |
| |
And we find that the optimal |
| |
combination of inputs is about |
| |
4.5% of |
| |
Ingredient four, 2% of |
| |
Ingredient 6. 2.2% of |
| |
Ingredient 8 and 1.24% of |
| |
Ingredient 9 using processing |
| |
method two. Let's review how |
| |
we've gotten here. We first |
| |
computed the missing response |
| |
columns. Then we found B-spline |
| |
models that fit those functions |
| |
well in the FDE platform. A |
| |
functional principal components |
| |
analysis determined that there |
| |
were four eigenfunctions |
| |
characterizing the variation in |
| |
this data. These four |
| |
eigenfunctions were determined |
| |
via the FPC profiler to each |
| |
have a reasonable subject |
| |
matter meaning. The functional |
| |
DOE analysis consisted of |
| |
applying pruned forward |
| |
selection to each of the |
| |
individual FPC scores using the |
| |
DOE factors as input variables. |
| |
And we see here that these have |
| |
found combinations of |
| |
interactions and main effects |
| |
that were most predictive for |
| |
each of the functional principal |
| |
component scores individually. |
| |
The Functional DOE Profiler |
| |
has elegantly captured all |
| |
aspects into one representation |
| |
that allows us to find the |
| |
formulation processing step that |
| |
is predicted to have desirable |
| |
properties as measured by high |
| |
yield and low impurity. |
| |
So now we can do an InfoQ |
| |
assessment of the |
| |
generalizability of the data in |
| |
the analysis. So in this case, |
| |
we're more interested in |
| |
scientific generalizability, as |
| |
the experimenter is a deeply |
| |
knowledgeable chemist working |
| |
with this compound. So we're |
| |
going to be relying more on |
| |
their subject matter expertise |
| |
then on statistical principles |
| |
and tools like hypothesis tests |
| |
and so forth. The goal is |
| |
primarily predictive, but the |
| |
generalizability is kind of |
| |
problematic because the |
| |
experiment wasn't designed. Our |
| |
ability to estimate interactions |
| |
is weakened for techniques like |
| |
forward selection and impossible |
| |
via least squares analysis of |
| |
the full model. Because the |
| |
study wasn't randomized, there |
| |
could be unrecorded time in |
| |
order effects. We don't have |
| |
potentially important covariate |
| |
information like temperature and |
| |
reaction time. This creates |
| |
another big question mark |
| |
regarding generalizability. |
| |
Repeatability and |
| |
reproducibility of the study is |
| |
also an unknown here as we have |
| |
no information about the |
| |
variability due to the |
| |
measurement system. Fortunately, |
| |
we do have tools like JMP's |
| |
evaluate design to understand |
| |
the existing design as well as |
| |
augment design that can greatly |
| |
enhance the generalization |
| |
performance of the analysis. |
| |
Augment can improve information |
| |
about main effects and |
| |
interactions, and a second round |
| |
of experimentation could be |
| |
randomized to also enhance |
| |
generalizability. So now I'm |
| |
going to go through a couple of |
| |
simple steps to show how to |
| |
improve the generalization |
| |
performance of our study using |
| |
design tools in JMP. Before I |
| |
do that, I want to point out |
| |
that I had to take the data and |
| |
convert it so that it was |
| |
proportions rather than in |
| |
percents. Otherwise the design |
| |
tools were not really agreeing |
| |
with the data very well. So we |
| |
go into the evaluate designer |
| |
and then we load up our Ys and |
| |
our Xs. I requested the ability to |
| |
handle second order interactions. |
| |
Then...yeah, I got this alert |
| |
saying, hey, I can't do that |
| |
because we're not able to |
| |
estimate all the interactions |
| |
given the one factor at a time |
| |
data that we have. So I backed |
| |
up. We go to the augment |
| |
designer, load everything up, |
| |
set augment. We'll choose and I- |
| |
optimal design because we're |
| |
really concerned with |
| |
predicted performance here. |
| |
And I |
| |
set the number of runs to 148. |
| |
The custom designer requested |
| |
141 as a minimum, but I went to |
| |
148 just to kind of make sure |
| |
that we've got all ability to |
| |
estimate all of our interactions |
| |
pretty well. After that, it |
| |
takes about 20 seconds to |
| |
construct the design. So now |
| |
that we have the design, I'm |
| |
going to show the two most |
| |
important diagnostic tools in |
| |
the augment designer for |
| |
evaluating a design. On the |
| |
left, we have the fraction of |
| |
design space plot. This is |
| |
showing that 50% of the volume |
| |
of the design has |
| |
a prediction variance that is |
| |
less than 1. So 1 would be |
| |
equivalent to the residual |
| |
error. So we're able to get |
| |
better than measurement error |
| |
quality predictions over the |
| |
majority of the design. On the |
| |
right we have the color map on |
| |
correlations. This is showing |
| |
that we're able to estimate |
| |
everything pretty well. There's |
| |
some...because of the mixture |
| |
constraint, we're getting some |
| |
strong correlations between |
| |
interactions and main effects. |
| |
Overall, the effects are fairly |
| |
clean. And the interactions are |
| |
pretty well separated from one |
| |
another, and the main effects |
| |
are pretty well separated from |
| |
one another as well. After |
| |
looking at the design |
| |
diagnostics, we can make the |
| |
table. Here, I have shown the |
| |
first 13 of the augmented runs |
| |
and we see that we've got...we |
| |
have more randomization. We don't |
| |
have use of the same main effect |
| |
over and over again streaks. |
| |
That's evidence of better |
| |
randomization and overall the |
| |
design is going to be able to |
| |
much better estimate the main |
| |
effects and interactions having |
| |
received better, higher quality |
| |
information in this second stage |
| |
of experimentation. So the input |
| |
variables, the Xs, are accurate |
| |
representations of the mixture |
| |
proportion, so that's a clear |
| |
objective interest. The |
| |
responses are close surrogate |
| |
for the amount of the product |
| |
and amount of impurity that's in |
| |
the batches. We're pretty good on |
| |
7.1. there. The justifications |
| |
are clear. After the study, we |
| |
can of course go prepare a |
| |
batch that is the formulation |
| |
that was recommended by the FDOE |
| |
profiler. Try it out and see if |
| |
we're getting the kind of |
| |
performance that we were looking |
| |
for. It's very clear that that |
| |
would be the way that we can |
| |
assess how well we've achieved |
| |
our study goals. So now under the |
| |
last InfoQ dimension |
| |
Communication. By describing the |
| |
ideal curve as a target |
| |
function, the Functional DOE |
| |
Profiler makes the goal and the |
| |
results of the analysis crystal |
| |
clear. But this can be expressed |
| |
at a level that is easily |
| |
interpreted by the chemists and |
| |
managers of the R&D facility. |
| |
And as we have done our detailed |
| |
information quality assessment, |
| |
we've been upfront about the |
| |
strengths and weaknesses of the |
| |
study design and data |
| |
collection. If the results do |
| |
not generalize, we certainly |
| |
know where to look for where the |
| |
problems were. Once you become |
| |
familiar with the concepts, |
| |
there is a nice add-in written |
| |
by Ian Cox that you can use to |
| |
do a quick quantitative InfoQ |
| |
assessment. The add-in has |
| |
sliders for the upper and lower |
| |
bounds of each InfoQ dimension. |
| |
These dimensions are combined |
| |
using a desirability function |
| |
approach for an overall interval |
| |
for the InfoQ over on the left. |
| |
Here is an assessment for the |
| |
data and analysis I covered in |
| |
this presentation. The add-in is |
| |
also a useful thinking tool that |
| |
will make you consider each of |
| |
the InfoQ dimensions. It's also a |
| |
practical way to communicate |
| |
InfoQ assessments to your |
| |
clients or to your management, as |
| |
it provides a high level view of |
| |
information quality without |
| |
using a lot of technical |
| |
concepts and jargon. The add-in |
| |
is also useful as the basis for |
| |
an InfoQ comparison. My |
| |
original hope for this |
| |
presentation was to be a little |
| |
bit more ambitious. I had hoped |
| |
to cover the analysis I had |
| |
just gone through, as well as |
| |
another simpler one, one where I skip |
| |
inputing the responses and doing |
| |
a simple multivariate linear |
| |
regression model of the response |
| |
columns. Today, I'm only able to |
| |
offer a final assessment of that |
| |
approach. As you can see, |
| |
several of the InfoQ |
| |
dimensions suffer substantially |
| |
without the more sophisticated |
| |
analysis. It is very clear that |
| |
the simple analysis leads to |
| |
much lower InfoQ score. |
| |
The upper limit of the simple |
| |
analysis isn't that much higher |
| |
than the lower limit of the more |
| |
sophisticated one. With |
| |
experience, you will gain |
| |
intuition about what a good InfoQ |
| |
score is for data science |
| |
projects in your industry and |
| |
pick up better habits as you |
| |
will no longer be blind to the |
| |
information bottlenecks in your |
| |
data collection, analysis and |
| |
model deployment. Information |
| |
quality with an easy to use |
| |
interface. This was my first |
| |
formal information quality |
| |
assessment. Speaking for myself, |
| |
the information quality |
| |
framework has given words and |
| |
structure to a lot of things I |
| |
already knew instinctively. It |
| |
is already changed how I |
| |
approach new data analysis |
| |
projects. I encourage you to go |
| |
through this process yourself on |
| |
your own data, even if that data |
| |
and analysis is already very |
| |
familiar to you. I guarantee |
| |
that you will be a wiser and |
| |
more efficient data scientist |
| |
because of it. Thank you. |