Candidate age and revealed preferences

As I’ve pointed out before, one really obvious problem with the endless hand-wringing about how Biden being three and a half years older than Trump must be a massive electoral liability is that in 2020 Democratic primary voters had many talented young candidates to choose from and yet gave more than 90% of their votes to candidates ranging from very old to extremely old. And in this election cycle, one candidate is underperfoming the polls in fundamentally non-competitive primaries and it ain’t Biden.

Still, presidential contests are inherently a small n. Perhaps in congressional elections voters have the strong preference for young candidates the press assumes they do? As Seth Masket argues, there’s no actual evidence for that either:

Since the “Biden is old therefore Biden can’t win” discourse doesn’t seem to have abated much lately, I thought I’d check to see if we had much evidence that being old actually hurts candidate vote shares. And it turns out we have a rather old legislature in Washington, DC with very high reelection rates, so that might be a good place to start.

Now, I’ll note that there are a number of survey-based studies showing that, all things being equal, voters prefer younger (under 70) candidates, although this effect is mitigated when two older candidates are close in age. While this is an important set of findings, all things are not usually equal. A Republican-leaning voter, for example, confronted with a choice between a 45-year old Democrat and a 75-year old Republican, may prefer a younger candidate in his heart of hearts, but will still vote for the elderly Republican ten times out of ten.

To get a sense of how age and vote shares interact, I obtained data on the current U.S. House of Representatives. I was interested in each member’s age, party affiliation, and vote share in 2022 (specifically, their share of the two-party vote). Just plotting out those two important variables gives us the scatterplot below. Each red dot is a Republican House member, and each blue dot a Democratic House member. The trend line is a moving average, giving us an idea of how votes shares change with age.

Okay, a couple of important things to see here:

• The trend line moves upward with age. That is, older officeholders tend to have somewhat higher vote shares. That doesn’t trend downward or flatten as the officeholders surpass 70 or even 80.
• There’s an interesting gap in the data on the lower right, where there just aren’t many old officeholders winning within less than 55% of the vote. My read on this is that those are very competitive districts, and those are not districts one grows old in; they tend to flip a fair amount and toss people into the private sector.
• There are a number of officeholders across the top of graph who were unopposed in 2022, and that seems to occur at a variety of ages.

This isn’t the most rigorous analysis so far, but one thing it doesn’t show is that voters turn against officeholders as they age. Yes, it’s possible that the most vulnerable elderly House members are nudged into retirement by their parties, but we know that parties very rarely push out their incumbents. Indeed, there are 11 House members in their 80s in the graph above.

Whatever one thinks voters should think — and there are certainly cases, especially in primary elections, where I would like voters to but more weight on new blood — in practice they seem to have no problem voting for older candidates, which helps to explain why we have this quasi-gerontocracy in the first place.