# Performing the VPC of categorical covariate

**URL:** <https://forum.certara.com/t/performing-the-vpc-of-categorical-covariate/3415>\
**Category:** NLME-NONMEM model comparisons\
**Created:** [June 14, 2019, 11:22am UTC](https://forum.certara.com/t/performing-the-vpc-of-categorical-covariate/3415 "2019-06-14T11:22:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![gwchoi](https://avatars.discourse-cdn.com/v4/letter/g/5fc32e/32.png) [@gwchoi](https://forum.certara.com/u/gwchoi)\
**Post date:** [June 14, 2019, 11:22am UTC](https://forum.certara.com/t/performing-the-vpc-of-categorical-covariate/3415/1 "2019-06-14T11:22:36Z")

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Dear all

I am currently working on the development of PopPK model of compound X to determine gender difference.

So I incorporated gender as a covariate in the model and gender affected the CL.

Therefore, I want to perform VPC by gender but how can I get the VPC result separated by gender?

Thanks to all in advance.

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**Author:** ![Samer\_Mouksassi](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Samer\_Mouksassi](https://forum.certara.com/u/Samer_Mouksassi)\
**Post date:** [June 14, 2019, 11:25am UTC](https://forum.certara.com/t/performing-the-vpc-of-categorical-covariate/3415/2 "2019-06-14T11:25:27Z")

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Hi you need to define the covariate as categorical using the user interface or in code :

fcovariate(gender())

then this covariate will be come available in the stratification options

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**Author:** ![gwchoi](https://avatars.discourse-cdn.com/v4/letter/g/5fc32e/32.png) [@gwchoi](https://forum.certara.com/u/gwchoi)\
**Post date:** [June 18, 2019, 8:17am UTC](https://forum.certara.com/t/performing-the-vpc-of-categorical-covariate/3415/3 "2019-06-18T08:17:08Z")

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Thanks smouksassi for your kind response.