In my earlier post, I noted the high reelection rate of House incumbents, even in year when voters are “angry.” In comments, several polisci types asked about retirements. Jeff Lazarus sums up the logic:
bq. For each election in the period 1946-2000, the mean number of House incumbents not returned to office is 69. There’s obviously significant variation; the number ranges from 34 in 1988 to 118 in 1948 and 110 in 1992. But on average 16% of the total House membership turns over each election. As for the strategic retirement issue, about half the departures every election are voluntary (again, with some variation), which includes both retirements and attempts to move to other offices. Generally I’m wary of any claims resting on the high reelection rates of incumbents, because those high rates are a by-product of selection bias: many/most incumbents who don’t think they can win select themselves out of the pool running for reelection. Lots of literature shows that retirees are those who are vulnerable and/or would have faced a strong challenger in the upcoming election.
How does taking account of retirements affect things? The data I’m using come from Gary Jacobson’s The Politics of Congressional Elections, which has data from 1946-2006. For each year, he reports the number of House members who sought reelection and the number who were defeated in the primary or general. Let’s assume — very generously — that every member who did not seek reelection was retiring strategically, even though many are not. They could be seeking higher office, for example. (Jeff L. may have better data, but this is what I have available.)
So add up the number of who didn’t seek reelection and the number of losers. Subtract that from 435. Divide by 435. Multiple by 100. That gives you the percentage of House members who were “returned” to office in the House.
Now here’s a comparable graph to the one I posted earlier, except excluding 2008 where I don’t have the same data:
Again, I predict a value for 2010. It is 76%.
This buttresses my point. Lots of people are talking about “angry” voters and the treacherous climate for incumbents. Very few people bother to mention that in this treacherous climate, the vast majority of incumbents will likely be returned to office.
A footnote: according to this count, the number of House members who are retiring or running for higher office is 40. If that is accurate, then 395 members are seeking or have sought reelection this year. That is _almost identical_ to the historical average for the 1946-2006 period (which is 398, according to Jacobson’s data). Whatever anti-incumbent sentiments exist, they haven’t translated into an abnormally high level of retirements.