# Standardization **URL:** \ **Category:** Day 2\ **Created:** [June 23, 2022, 12:26am UTC](https://isgw-forum.colorado.edu/t/standardization/372 "2022-06-23T00:26:32Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![hallerl1](https://isgw-forum.colorado.edu/letter_avatar_proxy/v4/letter/h/e8c25b/32.png) [@hallerl1](https://isgw-forum.colorado.edu/u/hallerl1)\ **Post date:** [June 23, 2022, 12:26am UTC](https://isgw-forum.colorado.edu/t/standardization/372/1 "2022-06-23T00:26:32Z")
Hi, I was wondering if there is a preference with regards to standardizing a phenotypic (continuous) variable when running a classical twin design and sex-limited twin design? Does the variable need to be standardized to work with the scripts and for best interpretation? Thanks! ---
**Author:** ![hmaes](https://isgw-forum.colorado.edu/letter_avatar_proxy/v4/letter/h/ebca7d/32.png) [@hmaes](https://isgw-forum.colorado.edu/u/hmaes)\ **Post date:** [July 11, 2022, 11:27pm UTC](https://isgw-forum.colorado.edu/t/standardization/372/2 "2022-07-11T23:27:54Z")
Hi Leora, There is no need to standardize your continuous variable prior to model fitting; the scripts work with the starting values you provide for the means and the variance components. If you’re estimating three variance components, divide the phenotypic variance by 3 for their starting values; or use a somewhat higher starting value for the VE component compared to the VC, VC or VD components. Please note that it’s assumed that the variables are normally distributed, thus a transformation might be warranted if the distributions of your variables are very skewed. Hermine. ---
**Author:** ![hallerl1](https://isgw-forum.colorado.edu/letter_avatar_proxy/v4/letter/h/e8c25b/32.png) [@hallerl1](https://isgw-forum.colorado.edu/u/hallerl1)\ **Post date:** [July 15, 2022, 12:56am UTC](https://isgw-forum.colorado.edu/t/standardization/372/3 "2022-07-15T00:56:00Z")
@hmaes This is incredibly helpful! Thank you!