# Gene Effect Question

**URL:** <https://forum.depmap.org/t/gene-effect-question/279>\
**Category:** Q&A\
**Created:** [November 5, 2020, 10:51pm UTC](https://forum.depmap.org/t/gene-effect-question/279 "2020-11-05T22:51:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ehazan1999](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@ehazan1999](https://forum.depmap.org/u/ehazan1999)\
**Post date:** [November 5, 2020, 10:51pm UTC](https://forum.depmap.org/t/gene-effect-question/279/1 "2020-11-05T22:51:03Z")

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Hi! I’m an undergrad doing research based on data in depmap. I was wondering if anyone can explain to me what gene effect is (how is it calculate, what does it mean, etc) and what a value closer or further away from 1 or 0 means (Achilles gene effect file). Thanks!

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**Author:** ![pmontgom](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.depmap.org/pmontgom/32/4_2.png) [@pmontgom](https://forum.depmap.org/u/pmontgom)\
**Post date:** [November 13, 2020, 9:22pm UTC](https://forum.depmap.org/t/gene-effect-question/279/2 "2020-11-13T21:22:29Z")

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For the details, the best source of information is the papers where the DEMETER (used to compute gene effect for RNAi data) and CERES (used to compute gene effect for CRISPR data) methods are described.

However, to give you a brief description to give you some intution, we’ve described how the values can be interpretted at the bottom of the “Dependent Cell Lines” tile on the gene page:

“Outcome from [DEMETER2](https://www.nature.com/articles/s41467-018-06916-5) or [CERES](https://www.nature.com/articles/ng.3984). A lower score means that a gene is more likely to be dependent in a given cell line. A score of 0 is equivalent to a gene that is not essential whereas a score of -1 corresponds to the median of all common essential genes.”