Many readers were incredulous when I pointed out that in the General Social Survey, the modal number of self-reported lifetime sexual partners equals 1.  Given the stereotype that men overstate and women understate on these matters, the pattern is solid: Can we really imagine that men’s true number is less than women’s reported number, or that women’s true number is more than men’s reported number?  Tyler Cowen demurred that both men and women understate their number of partners.

I was intrigued, then, to discover strong behavioral evidence that both men and women overstate a different measure of sexual activity: frequency.  In the New York Times, boils down the evidence:

I
analyzed data from the General Social Survey, a classic source.
Heterosexual men 18 and over say that they average 63 sex acts per year,
using a condom in 23 percent of them. This adds up to more than 1.6
billion heterosexual condom uses per year.

Heterosexual
women say they average 55 sex acts per year, using a condom in 16
percent of them. This adds up to about 1.1 billion heterosexual condom
uses per year.

Who is telling the truth, men or women?

Neither. According to Nielsen, fewer than 600 million condoms are sold every year.

Americans
may also be exaggerating how often they have unprotected sex. About 11
percent of women between the ages of 15 and 44 say they are sexually
active, not currently pregnant and not using contraception. Even with
relatively conservative assumptions about how many times they are having
sex, we would expect 10 percent to become pregnant every month. But
this would already be more than the total number of pregnancies in the
United States (which is one in 113 women of childbearing age).

Men
who have never been married claim to average 29 condom uses per year.
This is more than the total number of condoms sold in the United States
to married and single people combined.

Yes, Tyler can always say that both genders understate their number of partners but overstate their frequency.  But did he – or anyone for that matter – ever predict such a thing before hearing the facts?  If you know of such a source, please share in the comments.