# GLM Logistic Example, why divide by age by 10?

**URL:** <https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195>\
**Category:** version agnostic\
**Tags:** doc\
**Created:** [April 12, 2022, 3:20pm UTC](https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195 "2022-04-12T15:20:38Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Oliver](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/oliver/32/3849_2.png) [@Oliver](https://discourse.pymc.io/u/Oliver)\
**Post date:** [April 12, 2022, 3:20pm UTC](https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195/1 "2022-04-12T15:20:38Z")

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Hi all

I went over [this example](https://docs.pymc.io/en/v3/pymc-examples/examples/generalized_linear_models/GLM-logistic.html) again and in the lm full function they divide age by 10.

Thank you so much for any explanations and hints and apologies! I’m sure I"m missing something obvious once more, but I don’t see it.

🤗

Edit: Also, I find this a bit sparse: [Generalized Linear Models — PyMC3 3.11.5 documentation](https://docs.pymc.io/en/v3/api/glm.html) is there more documentation to the different attributes and modules, arguments etc. somewhere?

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**Author:** ![cluhmann](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/cluhmann/32/3083_2.png) [@cluhmann](https://discourse.pymc.io/u/cluhmann)\
**Post date:** [April 12, 2022, 5:24pm UTC](https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195/2 "2022-04-12T17:24:05Z")

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> [@Oliver](#):
>
> I’m sure I"m missing something obvious once more, but I don’t see it.

I’m not sure you are missing something obvious. There’s mention that it helped with model convergence, so I guess that’s a clue. If I had to guess, I might speculate that including raw age was ok, but also including age^2 might make it somewhat difficult to use similar priors over the different coefficients. But that’s just a guess.

> [@Oliver](#):
>
> is there more documentation to the different attributes and modules, arguments etc. somewhere

The GLM submodule is going away in v4 and users should migrate to [bambi](https://bambinos.github.io/bambi) instead.

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**Author:** ![Oliver](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/oliver/32/3849_2.png) [@Oliver](https://discourse.pymc.io/u/Oliver)\
**Post date:** [April 12, 2022, 5:29pm UTC](https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195/3 "2022-04-12T17:29:21Z")

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Thanks a lot!  
The link isn’t working, can you check? Sorry  
Edit: [BAyesian Model-Building Interface (Bambi) in Python — Bambi 0.7.1 documentation](https://bambinos.github.io/bambi/main/index.html) I think this one 🙂

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**Author:** ![cluhmann](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/cluhmann/32/3083_2.png) [@cluhmann](https://discourse.pymc.io/u/cluhmann)\
**Post date:** [April 12, 2022, 5:33pm UTC](https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195/4 "2022-04-12T17:33:54Z")

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Yup, should be fixed now.

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<div class="post-metadata">

**Author:** ![Oliver](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/oliver/32/3849_2.png) [@Oliver](https://discourse.pymc.io/u/Oliver)\
**Post date:** [April 12, 2022, 5:43pm UTC](https://discourse.pymc.io/t/glm-logistic-example-why-divide-by-age-by-10/9195/5 "2022-04-12T17:43:05Z")

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Thanks a lot bambi is awesome, so much easier!