Community research venues
Finding research
One approach to making use of research in communities is to keep an eye on specific conferences and journals that publish this type of work. Some of these publishing outlets are open access, and often pre-prints are available (i.e. a free 'just-before-published' copy). You can scan the titles and abstracts for work of interest and then dig up the article, a blog post related to the article, or a video of the work being presented. The authors of the work will (almost) always be thrilled to hear from you if you reach out to ask a question or request a copy of the article.
Finding answers
If you have a specific question and want to understand the evidence associated with that question, you might find Google Scholar a helpful resource -- whereas a general Google search may yield you a range of opinions, looking at academic articles will give you a sense of what people find when they take a more rigorous approach. You can filter by year and make use of quotation marks. For example, a search like "code of conduct" diversity "open source"
might help inform a discussion on whether codes of conduct in open source projects have a role to play in increasing diversity (short answer: a CoC can help, but it's not a guarantee).
Venues and sources
Here are some places that publish research about online communities.
Online Communities in General
-- ICWSM -- CHI -- CSCW -- AOIR -- Transactions on Social Computing
Software Communities
-- ICSE -- ICSA -- OpenSym -- MSR -- SANER -- FSE/ESE