# Clarification on the random variable W in the decoder

**URL:** <https://discourse.scverse.org/t/clarification-on-the-random-variable-w-in-the-decoder/3860>\
**Category:** General\
**Tags:** scvi\
**Created:** [November 10, 2025, 10:58pm UTC](https://discourse.scverse.org/t/clarification-on-the-random-variable-w-in-the-decoder/3860 "2025-11-10T22:58:16Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![ori-kron-wis](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.scverse.org/ori-kron-wis/32/1099_2.png) [@ori-kron-wis](https://discourse.scverse.org/u/ori-kron-wis)\
**Post date:** [November 11, 2025, 6:46am UTC](https://discourse.scverse.org/t/clarification-on-the-random-variable-w-in-the-decoder/3860/2 "2025-11-11T06:46:56Z")

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See if this helps:

> [@The mean of the the scVI ZINB model distribution (related to supplementary note 3)](https://discourse.scverse.org/t/the-mean-of-the-the-scvi-zinb-model-distribution-related-to-supplementary-note-3/3459/5):
>
> To bring more explanation in the supplement the definition is the logits total\_counts convention for a negative binomial (r, p and lambda instead of rho, theta and l\_n). See our code on how this changes computation: [scvi-tools/src/scvi/distributions/\_negative\_binomial.py at main · scverse/scvi-tools · GitHub](https://github.com/scverse/scvi-tools/blob/main/src/scvi/distributions/_negative_binomial.py#L336-L479). To make it very short, theta is the mean variance relationship and the mean is independent of theta.

In short, there is some confusion of the notations of the supplemental section

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