Not hugely surprising, but we find—in running regressions on every House race since 1998 and every Senate race since 1990—that the importance of candidate-quality measures is decreasing, while the importance of state or district partisanship is increasing.

The candidate quality measures we use in our model are experience (highest elected office held), fundraising and the presence/absence of scandals. All of those are becoming LESS predictive. In general, the incumbency advantage is decreasing, also.

We find that there still *is* an advantage from casting more votes across party lines, i.e. moderates and "mavericks" continue to overperform other factors held equal, but there is so much party-line voting these days that few members of Congress fall into that bucket anymore.

Incidentally, you may notice that a LOT of the prominent Senate challengers this year have little or no experience in elected office. That doesn't seem to be as much of a disadvantage as it once was. You can run a perfectly decent campaign as a "generic" Democrat or Republican.