Notes

This table shows the average change in partisanship for the 329 districts in which incumbents are running for re-election in 2002 and for which we have data on the 2000 and 2002 district partisanship.  The table shows the average change in partisanship for all seats held by Democrats and Republicans in each state and the average change for safe and competitive seats held by each party.  Safe seats are defined as seats whose leaning suggests at least a 55%-45% margin for the incumbent party.  Competitive seats are all those seats than have less than a 10% advantage for the incumbent party. All changes are from the perspective of the incumbent party:  positive changes means that the seats became safer for the incumbent; negative changes mean the seats became less safe for the incumbent party.

Example:  California

California’s 19 Republican seats became on average 1.6% more Republican and the 31 Democratic seats became 0.3% more Democratic.  The 10 safe R seats and the 25 safe D seats actually became less safe for the incumbents, while the 9 competitive R seats and the 6 competitive D seats all became safer for the incumbents.  In other words, incumbents were protected.