# Why is the Chronos dependency score smaller than -1?

**URL:** <https://forum.depmap.org/t/why-is-the-chronos-dependency-score-smaller-than-1/2907>\
**Category:** Q&A\
**Created:** [November 5, 2023, 2:16am UTC](https://forum.depmap.org/t/why-is-the-chronos-dependency-score-smaller-than-1/2907 "2023-11-05T02:16:33Z")\
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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 28, 2023, 8:44pm UTC](https://forum.depmap.org/t/why-is-the-chronos-dependency-score-smaller-than-1/2907/2 "2023-11-28T20:44:12Z")

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If you’re interested in making a binary call on whether a gene is essential or not, you probably should use the “Probability of gene dependency” instead of “Gene Effect”.

See the the guidance at [DepMap Genetic Dependencies FAQ](https://forum.depmap.org/t/depmap-genetic-dependencies-faq/131) for more explanation. (It was written when the method we used to compute “Gene Effect” was CERES and although we now use a newer method, Chronos, the advice given is still valid.)

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