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Value below the detection threshold and statistical analysis on JMP

Good morning,

For a study, several values ​​(continuous numbers) are below the detection threshold.

What is the recommended statistical method for using this data?

Which application on JMP?

Thank you very much for your advice.

CEB

Basic Data Analysis and ModelingRe: Valeur en dessous du seuil de détection et analyse statistique sur sur JMP

Hi @CEB87,

 

Welcome in the Community !

 

You can use Detection Limits in your response column property to define a lower and/or upper threshold beyond which a response cannot be measured.

When using Generalized Regression models (JMP Pro) in the Fit Model platform, this property (and corresponding values) will be used to create censored values when observation is oustside of these limits. You can watch the presentation Limits of Detection (LoD) - New in JMP Pro 16 to get a better understanding of the benefit to use detection limits in modeling.

 

Hope this answer will help you,

Re: Value below the detection threshold and statistical analysis on JMP

Thanks @Victor_G

This feature is not available on JMP 12. Another way to do it?

THANKS

CEB

Re: Valeur en dessous du seuil de détection et analyse statistique sur sur JMP

I'm not familiar with the options available in JMP12, but you could probably use Quantile Regression to deal with censored values in the Generalized Regression options.

The idea is either to use a regression model that doesn't estimate the conditional mean of the response variable across factors values, as it will be biased towards censored values (unlike estimating conditional median in Quantile Regression), and/or lower the importance of the censored data points on the model fit (to avoid the leverage effects of these censored values points).

 

Hope this answer will help you,