How to best support field-specific Stan communities on Discourse

I was asked by @vianeylb who is trying to kickstart Stan community for ecology how to best support such communities here on Discourse. I am convinced we need to support field-specific communities here, the question is how. This turned out to not have a clear best answer and potentially invites for some restructuring of the forums and thus warrants further discussion with the broader community. As you may have noted in my status update from January I didn’t want to invest energy into thinking about Discourse structure at this time, but I think @vianeylb’s effort is a good reason to consider changing priorities.

I see only two sensible options (except for “don’t do anything”). In the following I will use Ecology as the main example, but everywhere “Ecology” is mentioned, I mean “Ecology” or other field with a Stan community.

1) Field Categories

A category is possibly the most prominent place to gather a discussion around a topic. When a new user posts, it is hard to miss that a relevant category exists. Filtering by categories is also the easiest to do.

The main problem I see with Ecology (or any other field) as a category is that currently the Discourse categories are organized in a way that is not really compatible with having categories around fields. “Ecology” cuts across Modelling, Interfaces, Publicity… It could also be confusing to users - if I fit my ecology model in brms, where should I post? And sometimes I might benefit from people outside of ecology looking at my model. Maybe having field-specific categories under “General” or a new “Field-specific” top-level category might work to an extent. This would assume that modelling-specific and interface-specific questions still go to the original categories, which might actually be desirable.

But maybe a bigger change of structure is warranted: the current forum categorization is IMHO not very functional, as - except for the Developers category - very few people can actually use categories to see only stuff they are interested in (the Jobs and Announcements categories also IMHO work well but have very low traffic). The exception are people maintaining interfaces who I presume follow the relevant categories. Rearranging the structure across fields/application areas (and use tags to mark interfaces, modelling, …) might be an improvement in this respect. I imagine there is a bunch of people who would only read a “Biology” or “Marketing” subcategory. I’d be happy to hear how people use the currently existing categories - maybe I am mistaken. This would however be a major change and if an agreement is reached that this is the better option, some more discussion on how to actually go about the restructuring will be held, so unless you believe it is important for this topic I don’t want to go into many details of how that would look like.

2) Field Tags

Another option would be to group Ecology topics by a tag. This nicely fits with the current structure as tags can cut across categories. You can “watch” a tag (so you get notified of new posts) etc. The biggest downside is that tags could be missed by novice users (and sometimes also advanced users). To some extent we could mitigate this by having better post templates and introductory posts, but still many users could totally miss that tags are a thing. We also currently don’t use tags much, but this could change if we want to. In that sense the effort involved in making field-specific tags useful and widely used could be of similar magnitude as the one required to restructure the categories system.

Meta: Which fields should be represented?

With both tags and categories, the question is how fine a structure should we have - is “Ecology” a category? Or should it be subcategory of “Life sciences”? Should “Microbial ecology” be a separate category/tag? I believe the best answer is to provide a few high-level categories/tags by default and create finer subdivisions/new branches whenever someone steps up as a moderator/maintainer/leader of the respective community (as Vianey did for ecology).

Looking forward to you thoughts on this.


Great idea and we should not let implementation details get in the way of making this happen. This could go a long way to engaging users in the discussion and creating more user-to-user dialog. I do not monitor all forums, but I would monitor and contribute to marketing discussions.

My (weak) opinion is that we should simply add categories for fields to the existing categories. This can happen organically as users within fields step up to monitor field-specific categories. I expect users will naturally know whether they have a question that would benefit from field experts or is of broader interest.

As to which categories, I’d also let that evolve organically. When there is someone who is willing to monitor a field-specific community, then they will know best how to label the field for their intended audience and how broad or narrowly to define it. The field categories do not need to be comprehensive or non-overlapping, IMO.


I think tags would be the best option, as it would provide more flexibility for users asking questions. It could be particularly helpful for people with multi-disciplinary problems.
Is there some way to adjust the Discourse interface so that tags become more obvious when creating posts? It could also be helpful to organize tabs into boxes for different types (e.g., “Field: Ecology, Marketing, Psychology, …”; “Models: Regression, Gaussian Process, HMM, Multivariate, …”).


One of the most unique and wonderful aspects of Discourse is the accessibility and responsiveness of authoritative experts on a wide range of problems. As an ecologist myself, I would love to see a specific niche for ecology on Discourse, but I would hate to see such a development result in less expert attention to challenges implementing ecological models in Stan. I expect to use this forum in the future when I run into a really challenging issue implementing an ecology-specific model in Stan. Can we be confident that the resident experts here, many (most? all?) of whom are not ecologists, would be likely to monitor traffic and remain responsive in an ecology-specific niche within Discourse? Will I need to fret about whether my question is worth troubling the “super duper Stan experts” in a non-ecological channel?

For these reasons, I am inclined to imagine that a tag would be more useful and inclusive than a new category.


Thanks everybody for weighing in. I agree with all the points put forward. First, a few minor followups on what you had to say:

Totally agree, it is currently my responsibility to no let this happen and you are welcome to keep me accountable for it.

Thinking about this more, I would be slightly reluctant to do this as the category drop down in “New Topic” is already quite crowded. If categories are chosen as the way forward, I would have a mild preference towards turning some of the categories we have now into tags.

First we would need to either let users create tags or pre-populate with a broad set of tags. It also seems Discourse can enforce a minimum number of tags per post. Discourse also lets you restrict tags to specific categories, let the user add only one of a group of tags (say field tags) or have a parent-child relationship where for example ecology-specific tags could be added only if “ecology” is tagged as well.
We can also display popular tags on the homepage and elsewhere, but that’s about all the tag fancy I could find.

While I agree this might be an issue, I believe it is not very serious. I can’t speak for others with certainty, but I personally currently monitor all categories and I believe many other devs/active users mostly do this as well. Although there are exceptions - I believe @paul.buerkner focuses heavily on the brms category and I assume other interface developers follow their respective categories as well.

It appears there is neither a strong consensus nor a strong dislike for any of the alternatives. I will let the topic sit for a few more days and then try to propose a specific way forward. I’ll also ask the community Leaders (@maxbiostat, @Ara_Winter, @emiruz, @andre.pfeuffer, @arya, @Max_Mantei) to weigh in if they have some preference or just experience to share.


Thanks @martinmodrak for laying out the category/tag question so clearly. An “Ecology” tag seems like a good solution to me.



“Ecology” seems like a useful level of detail for a field-specific tag. “Life sciences” may be too broad, and “Microbial ecology” too specific.

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I currently believe the best way forward is to use tags as that would cause the least disruption to the existing forum structure. I’ll prepare the necessary technicalities (especially create a usable set of tags), expect a public announcement topic in a few days.

BTW, the ecology tag already exists for a while (but was used only once :-), so you can set yourself to “watching” or “tracking” on the tag’s page

Thanks for everybody’s patience.



I’d expect adapting tags for sciences for instance would result in most areas being pretty sparse for some time. Meanwhile, I suspect that rooting a model too closely to a field may make it less discoverable to those for whom the model is useful but who are outside of their field, and may make the explanations / descriptions too field specific to solicit broad engagement. E.g. if a biologist ends up addressing the biology subset in biology language it may be tough for non biologists to engage even if they can help.

Personally, I’ve learned a huge amount over the past 6 months from the forum directly, but mostly because I am on it every day, and so I can engage with what I find interesting and ignore what I don’t as it comes in. If I wanted to replicate some of that benefit in a field specific way to others what I’d do is curate a “best of” page for say “bioinformatics” that had clear questions and clear solutions and then directly engage with what I felt were representative members of that field now and then to work out what my page was missing. So an ability to vote a response as a “best of” would be a neat forum feature.

I thing the end result should be something like the Stan user manual for example, but for “bioinformatic modelling” and consisting mostly of curated links with brief descriptions. More simply, if there was a way of flagging the “best of”, it could also be a sticky with a set of filters for different fields / models / etc.

Another thing that may be worth doing is to institute more leaders/moderators that are aligned to specific fields with more field specific goals that involve things like curation and perhaps just understand how the field is represented on Stan.


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By the way, I cannot add new tags to the list by myself, right?
It would be nice to add a cogsci (or cognitive-science) tag, it would be great to be able to discover people working on problems of cognitive modeling.

Yes, we currently only allow tag creation for Regular (TL 3, i.e. very active) users and above. But you can definitely send me private message with some links to post or keywords to search that you think should populate the tag and I’ll be happy to add it!