The Juris Lab has a nice, approachable statistical overview of federal civil case disposition over the past twenty years. It notes that the “average” case takes about 344 days from filing to termination, although that number varies widely depending on case type, jurisdiction, and nature of disposition. (Cases ending in a trial verdict take another year to resolve on average.)
The oveview does not attempt to account for all the variation in disposition time, and does not even mention obvious factors like judicial vacancies, complex procedural settings like MDLs, the influence of ADR on filings, CJRA-style reporting pressure, or settlement pressure. But it is still very useful.
I have only recently come across The Juris Lab, which aims to wed legal issues with big data. It seems like a promising site, and worth checking out on a regular basis.