Here at the Reporting Group, we’ve always wanted to tie the fundraising invitations in our Party Time database to actual donations reported to the Federal Election Commission by a politician or a political action committee--to be able to show a donor gave money to a politician at a certain event.
It’s nearly impossible, and there's a number of reasons we can't--not least of which is that dates in FEC records don't necessarily correspond to the day a contribution was given. (See here for an explanation.) Even when there's a disclosure intended to shed light ...