# Mcmc\_plot intervals with thicker CI lines?

**URL:** <https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139>\
**Category:** brms\
**Tags:** bayesplot\
**Created:** [June 21, 2020, 7:34pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139 "2020-06-21T19:34:21Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![quantumlinguist](https://avatars.discourse-cdn.com/v4/letter/q/e47c2d/32.png) [@quantumlinguist](https://discourse.mc-stan.org/u/quantumlinguist)\
**Post date:** [June 21, 2020, 7:34pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/1 "2020-06-21T19:34:21Z")

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I’m plotting the posterior distribution intervals of my model but when I paste the plot in Word the credible interval lines are too thin and you can barely see them. How can I make them thicker? and the dot showing the mean/median bigger? I have customized other parts with ggplot but I can’t figure out how to change this. Thanks.

- Operating System: Mac
- brms Version: 2.13.0

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**Author:** ![Christopher-Peterson](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/christopher-peterson/32/13_2.png) [@Christopher-Peterson](https://discourse.mc-stan.org/u/Christopher-Peterson)\
**Post date:** [June 21, 2020, 7:57pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/3 "2020-06-21T19:57:43Z")

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Have you looked at the [vignette](https://cran.r-project.org/web/packages/bayesplot/vignettes/plotting-mcmc-draws.html)? The `probs` and `probs_outer` arguments seem to be what you’re looking for. They should work with `mcmc_plot()` as well

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**Author:** ![quantumlinguist](https://avatars.discourse-cdn.com/v4/letter/q/e47c2d/32.png) [@quantumlinguist](https://discourse.mc-stan.org/u/quantumlinguist)\
**Post date:** [June 21, 2020, 7:59pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/4 "2020-06-21T19:59:17Z")

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yes I have, but that only takes care of the percentage for each interval. I don’t think you can change the thickness of the lines or the size of the dot for that matter.

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**Author:** ![Christopher-Peterson](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/christopher-peterson/32/13_2.png) [@Christopher-Peterson](https://discourse.mc-stan.org/u/Christopher-Peterson)\
**Post date:** [June 21, 2020, 8:05pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/5 "2020-06-21T20:05:25Z")

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Oh wow, I totally misread your question.

Looking at the function’s [source code](https://github.com/stan-dev/bayesplot/blob/master/R/mcmc-intervals.R), it appears that there isn’t a way to do this. If you’re feeling adventurous, you could probably make a custom version of the function, modify the `size` argument of `args_inner` and `args_outer`, and put `bayesplot:::` in front of any function that R doesn’t recognize.

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<div class="post-metadata">

**Author:** ![quantumlinguist](https://avatars.discourse-cdn.com/v4/letter/q/e47c2d/32.png) [@quantumlinguist](https://discourse.mc-stan.org/u/quantumlinguist)\
**Post date:** [June 21, 2020, 8:10pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/6 "2020-06-21T20:10:27Z")

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OK, I will try that! Thanks

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**Author:** ![jonah](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/jonah/32/200_2.png) [@jonah](https://discourse.mc-stan.org/u/jonah)\
**Post date:** [June 21, 2020, 8:39pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/7 "2020-06-21T20:39:10Z")

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I’m not opposed to adding this to bayesplot (it might just have been an oversight originally). So if you want to open an issue on github with a feature request or even submit a pull request (if you do end up making this change yourself like @Christopher-Peterson suggested) then that would definitely be welcome!

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<div class="post-metadata">

**Author:** ![quantumlinguist](https://avatars.discourse-cdn.com/v4/letter/q/e47c2d/32.png) [@quantumlinguist](https://discourse.mc-stan.org/u/quantumlinguist)\
**Post date:** [June 21, 2020, 8:49pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/8 "2020-06-21T20:49:20Z")

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Thanks, I just submitted a feature request. How do I know when this feature is added? As I’m writing a paper and I need this plot, thank you!

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**Author:** ![jonah](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/jonah/32/200_2.png) [@jonah](https://discourse.mc-stan.org/u/jonah)\
**Post date:** [June 21, 2020, 9:06pm UTC](https://discourse.mc-stan.org/t/mcmc-plot-intervals-with-thicker-ci-lines/16139/9 "2020-06-21T21:06:33Z")

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I had a free moment now, so I just added this on a branch in the bayesplot github repo. I responded over on GitHub but I’ll put it here too for anyone else interested on the forums:

If you install that branch of bayesplot using

```
devtools::install_github("stan-dev/bayesplot", ref = "mcmc_intervals-size")

```

then you should be able to use the new arguments `inner_size`, `outer_size`, and `point_size`. Does that do what you were looking for? Sometime soon I’ll make this into a pull request and so we can get it into the next release, but you should be able to use the version on that branch in the meantime.