Does anyone know if there exists a comparison tool regarding the coverage of the major online subscription databases (such as Quicklaw and Westlaw)? I am envisioning a simple tool that would indicate their coverage of various courts over time, so one could know at a glance which database to consult for finding a particular case. I know that each database documents its own scope, but I was wondering if anyone out there has undertaken the project of compiling that information into a quick comparison chart. I realize that it would be a lot of work to keep up-to-date, but I thought perhaps an enterprising librarian might have already taken up the challenge. If so, please advise. Or if you have any other advice on this topic, please share. Thanks!