# Reference essential genes for Chronos score scaling

**URL:** <https://forum.depmap.org/t/reference-essential-genes-for-chronos-score-scaling/2512>\
**Category:** Q&A\
**Created:** [May 2, 2023, 1:20pm UTC](https://forum.depmap.org/t/reference-essential-genes-for-chronos-score-scaling/2512 "2023-05-02T13:20:05Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Allan\_Lui](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.depmap.org/allan_lui/32/836_2.png) [@Allan\_Lui](https://forum.depmap.org/u/Allan_Lui)\
**Post date:** [May 2, 2023, 1:20pm UTC](https://forum.depmap.org/t/reference-essential-genes-for-chronos-score-scaling/2512/1 "2023-05-02T13:20:05Z")

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What genes are used as reference essential genes to scale the DepMap Chronos gene effect scores?  
Is it the genes listed in AchillesCommonEssentialControls.csv or CRISPRInferredCommonEssentials.csv?

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**Author:** ![Joshua\_Dempster](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.depmap.org/joshua_dempster/32/19_2.png) [@Joshua\_Dempster](https://forum.depmap.org/u/Joshua_Dempster)\
**Post date:** [May 2, 2023, 6:16pm UTC](https://forum.depmap.org/t/reference-essential-genes-for-chronos-score-scaling/2512/2 "2023-05-02T18:16:53Z")

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It’s the AchillesCommonEssentialControls. CRISPRInferredCommonEssentials are the genes determined to be common essential from the screens themselves.