# How many Stan users are there?

**URL:** <https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196>\
**Category:** General\
**Created:** [December 5, 2019, 4:46pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196 "2019-12-05T16:46:57Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![s.maskell](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/s.maskell/32/6626_2.png) [@s.maskell](https://discourse.mc-stan.org/u/s.maskell)\
**Post date:** [December 5, 2019, 4:46pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/1 "2019-12-05T16:46:57Z")

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It seems we could look at a number of pre-existing data sources (eg discourse views and contributors, papers, StanCon attendance etc) to inform an inference of how many people use Stan (and/or use things that use Stan). We could also generate new data (eg via surveys etc). Do we know the answer and/or how best to work it out?

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**Author:** ![lauren](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@lauren](https://discourse.mc-stan.org/u/lauren)\
**Post date:** [December 5, 2019, 4:55pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/2 "2019-12-05T16:55:40Z")

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I’ve thought a tonne about surveying the Stan community or potentially capture-recapture techniques, but generating new data in this way would be a lot of work and my current funding wouldn’t cover it (that’ll change next year though!). I’d be interested in collaborating if anyone is interested. :)

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**Author:** ![s.maskell](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/s.maskell/32/6626_2.png) [@s.maskell](https://discourse.mc-stan.org/u/s.maskell)\
**Post date:** [December 5, 2019, 6:08pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/3 "2019-12-05T18:08:45Z")

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As is hopefully obvious, i am keen to help. I can probably deploy people on this who can help make this happen if we know what it is that we needed them to do.

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**Author:** ![avehtari](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/avehtari/32/5935_2.png) [@avehtari](https://discourse.mc-stan.org/u/avehtari)\
**Post date:** [December 5, 2019, 6:20pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/4 "2019-12-05T18:20:02Z")

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How about asking who has registered to discourse? From that we could extrapolate the population size for those who we could reach by survey?

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**Author:** ![s.maskell](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/s.maskell/32/6626_2.png) [@s.maskell](https://discourse.mc-stan.org/u/s.maskell)\
**Post date:** [December 5, 2019, 7:11pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/5 "2019-12-05T19:11:06Z")

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@avehtari: who would we survey and how would we get the survey to them? I feel I am being dim.

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**Author:** ![lauren](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@lauren](https://discourse.mc-stan.org/u/lauren)\
**Post date:** [December 5, 2019, 9:33pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/6 "2019-12-05T21:33:04Z")

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From memory the hope was to utilized a snowball survey (once you finish you forward onto other people in the population), which is generally what you use when you have a hard to define population.  
One of the stats grads here, Jonathan Auerbach and I talked about starting multiple snowballs (Andrew’s blog, Discourse, Twitter, StanCon mailing lists, etc.) and then tracking what snowball people were recruited by (and if multiples) as a way of measuring coverage.

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**Author:** ![andrewgelman](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/andrewgelman/32/1577_2.png) [@andrewgelman](https://discourse.mc-stan.org/u/andrewgelman)\
**Post date:** [December 6, 2019, 4:53am UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/7 "2019-12-06T04:53:41Z")

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This is a fascinating statistics question. Maybe I could post a blog on this and see if there are any thoughts.

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**Author:** ![jroon](https://avatars.discourse-cdn.com/v4/letter/j/fbc32d/32.png) [@jroon](https://discourse.mc-stan.org/u/jroon)\
**Post date:** [December 6, 2019, 9:26am UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/8 "2019-12-06T09:26:57Z")

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@lauren I think you should name that design a snowball fight 😂

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**Author:** ![lauren](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@lauren](https://discourse.mc-stan.org/u/lauren)\
**Post date:** [December 6, 2019, 12:12pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/9 "2019-12-06T12:12:54Z")

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That’s a fantastic name!!!

@andrewgelman you can, it’d be interesting to see what folks think.

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**Author:** ![Bob\_Carpenter](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/bob_carpenter/32/9230_2.png) [@Bob\_Carpenter](https://discourse.mc-stan.org/u/Bob_Carpenter)\
**Post date:** [December 7, 2019, 2:49am UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/10 "2019-12-07T02:49:27Z")

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What’s your definition of a Stan user? Is it someone who once downloaded Stan and ran a model? Or is it someone who uses Stan regularly, and if so, how regularly? What about people who use packages like brms or rstanarm or prophet that are built on top of Stan?

There are over 3K users registered on Discourse, but that doesn’t mean they’re regulars. Many of them only showed up once.

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**Author:** ![andrewgelman](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/andrewgelman/32/1577_2.png) [@andrewgelman](https://discourse.mc-stan.org/u/andrewgelman)\
**Post date:** [December 7, 2019, 3:23am UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/11 "2019-12-07T03:23:29Z")

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Blog post on the topic scheduled for Monday.

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**Author:** ![s.maskell](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/s.maskell/32/6626_2.png) [@s.maskell](https://discourse.mc-stan.org/u/s.maskell)\
**Post date:** [December 7, 2019, 8:16am UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/12 "2019-12-07T08:16:28Z")

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For context, UK academic departments (eg the one I sit in) are assessed (as part of the “Research Excellence Framework”, REF) on the basis of some criteria: the next assessment is imminent, but the one after that will be in 2026. When aggregated over each entire University, the outcome of that assessment process modulates the amount of (Quality-related Research, QR) income that the University receives from the UK government. So, it’s important to inform the assessment process with pertinent information.

One of the three assessment criteria is “impact”, which relates to the uptake of academic research outside of the academic discipline it came from and is metricated in terms of “reach and significance” during the census period. Unfortunately, “reach and significance” is not defined quantitatively. However, the notion of the census period is defined as people using the research during a specified period of time (eg 2021-2026).

The specific motivation for my question is that I’d like to understand how we (locally to my department) could quantify the “reach and significance” of any enhancements to Stan that (we hope!) might come out of our work between now and 2026. It seems natural to start by finding out what we (as the Stan community) know about how big we are now.

So, in answer to your question, I think I’d ideally like to know how many people and/or organisations are making use of specific subsets of Stan’s code (including in any packages that use Stan) during a specified period. I’d also like to know where they are based geographically, whether people work in academic, industry or government, the demographic of applications they are working on, etc etc.

That’s clearly hinting at scope creep, but hopefully helps explain the specific reason I asked the question, which I see as an important step towards quantifying the impact of our work to help enhance Stan.

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<div class="post-metadata">

**Author:** ![lauren](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@lauren](https://discourse.mc-stan.org/u/lauren)\
**Post date:** [December 9, 2019, 1:05pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/13 "2019-12-09T13:05:27Z")

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I think this would be relevant outside of the REF as well - a useful addition to many grants/impact sections.

> [@s.maskell](#):
>
> So, in answer to your question, I think I’d ideally like to know how many people and/or organisations are making use of specific subsets of Stan’s code (including in any packages that use Stan) during a specified period. I’d also like to know where they are based geographically, whether people work in academic, industry or government, the demographic of applications they are working on, etc etc.

We were at the point where we were focussing on questions around this, plus an emphasis on barriers to entry. I can dig them up if there’s renewed interest. I believe the conclusion last time was that the time-cost of doing it wasn’t worth the expected benefit, but it could have changed! :)

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**Author:** ![andrewgelman](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/andrewgelman/32/1577_2.png) [@andrewgelman](https://discourse.mc-stan.org/u/andrewgelman)\
**Post date:** [December 9, 2019, 8:40pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/14 "2019-12-09T20:40:25Z")

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I posted my question here: [https://statmodeling.stat.columbia.edu/2019/12/09/how-many-stan-users-are-there/](https://statmodeling.stat.columbia.edu/2019/12/09/how-many-stan-users-are-there/)

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**Author:** ![avehtari](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/avehtari/32/5935_2.png) [@avehtari](https://discourse.mc-stan.org/u/avehtari)\
**Post date:** [December 10, 2019, 10:56am UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/15 "2019-12-10T10:56:19Z")

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This paper might have useful ideas [Using an Online Sample to Estimate the Size of an Offline Population](https://link.springer.com/article/10.1007/s13524-019-00840-z) how to estimate the number of those users who would be unlikely to be reached by survey.

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**Author:** ![mitzimorris](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/mitzimorris/32/29_2.png) [@mitzimorris](https://discourse.mc-stan.org/u/mitzimorris)\
**Post date:** [December 12, 2019, 12:47pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/16 "2019-12-12T12:47:53Z")

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Stack Overflow has tag “Stan” and 254 users (if I’m interpreting their graphics correctly) have listed Stan as things they’re interested in. about once a week someone asks a Stan question.

 ![Untitled](https://canada1.discourse-cdn.com/flex030/uploads/mc_stan/original/2X/9/9300720a47a4b33d01838c972954e8cf48ffde5b.png)

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**Author:** ![mcol](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/mcol/32/5598_2.png) [@mcol](https://discourse.mc-stan.org/u/mcol)\
**Post date:** [December 12, 2019, 12:56pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/17 "2019-12-12T12:56:50Z")

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254 is the number of questions with that tag, the number of users will be less than that.

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**Author:** ![mitzimorris](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/mitzimorris/32/29_2.png) [@mitzimorris](https://discourse.mc-stan.org/u/mitzimorris)\
**Post date:** [December 12, 2019, 3:48pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/18 "2019-12-12T15:48:00Z")

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doh!  
users do list their interests, but no way to scrape that out of SO.

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**Author:** ![lauren](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@lauren](https://discourse.mc-stan.org/u/lauren)\
**Post date:** [December 12, 2019, 4:15pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/19 "2019-12-12T16:15:55Z")

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It’s an interesting question! We might want to think about targeting this question using a statistical/surveying method and then benchmarking our population estimates against other potential indicators as another coverage check (number of downloads of Stan in R packages relative to Python etc.).

One of the challenges for this is agreeing upon what the definition of a Stan user is.

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<div class="post-metadata">

**Author:** ![lauren](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@lauren](https://discourse.mc-stan.org/u/lauren)\
**Post date:** [December 12, 2019, 7:38pm UTC](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196/20 "2019-12-12T19:38:13Z")

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I think we’re going to have a hangouts meeting on this topic to see if we can make some sort of plan. I’ve emailed folks who’s email I have but for those interested we’re picking a time here, and if you put your full name in I can probably google your email for an invite. :) [https://www.when2meet.com/?8493674-nr5Ai](https://www.when2meet.com/?8493674-nr5Ai)

[Next page](https://discourse.mc-stan.org/t/how-many-stan-users-are-there/12196.md?page=2)