fractional factorial design with 3 or more level continuous factors

Question

Hello,

a customer is asking if JMP allows to do fractional factorial designs with 3 or more level continuous factors (no component, with component (different levels). Or alternatively,

is it possible to use the fractional design it generates in the full factorial design set up and will it still be able to generate reliable data?

Thanks a lot,

Valerie

Ryan_Lekivetz · Answer

I would agree with Malcolm's thoughts on getting a sense of those higher order effects.

One thing that tends to come up along with this is that the values in the middle (whether continuous or discrete numeric) won't show up as often.

An exception is the main effects screening designs from the screening design platform: it uses the values of discrete numeric factors equally often, but you would need to check design evaluation to see about higher order terms.

Peter_Bartell · Answer

The key word I'm going to focus in here in your request is 'reliable data'. The customer may want to spend some time using the Design Evaluation tools BEFORE running the experiment to compare different aspects of the design's power, aliasing, and so forth. Melded with their process knowledge this sort of pre experimental execution work can help them have the highest degree of confidence that their specific experimental goals and objectives have a 'reliable' chance of being achieved. So Malcolm's ideas are spot on to generate candidate designs...but I'd sure spend some time evaluating various candidate designs.

malcolm_moore1 · Answer

Also if they have a large number of factors it will be costly in terms of total number of experimental runs to model many higher order effects. So best to also ask them what is the cost of an experimental run and if they have any limitations on their experimental budget.