Contributing to non-profit groups

We were approached by Progressive Maryland Education Fund for a contribution the other day. I was thinking that it would be nice if there were a database for non profits such as these so that it can help me decided whether to give -- similar to the BBB's database on charities. On an related note, PMEF supports living wage and campaign finance reform but I wonder how much they and others like them such as PIRG, MaryPIRG and other so-called non-profit groups are paying their canvassers to go door to door soliciting funds. I should have asked. Next time I will and I'd suggest that these organizations start registering with the BBB with their financial information.