The Gager/Yabiku study is a perfect example since their findings more or less contradict "common wisdom." Indeed, instead of finding that household labor and sexual frequency are inversely related (i.e. as the former increases, the latter decreases), they found the exact opposite: the busier couples seemed to be, both in terms of housework and career work, the more sex they had. It's the "work hard/play hard" theory which Gager/Yabiku describe as the "multiple spheres" hypothesis (I'll explain this in a second).
Going into their study (which uses National Survey of Families and Households data), Gager/Yabiku had three hypotheses they wanted to test:
1) Time Availability. This is the "intuitive" theory: you work more, you have sex less because you have less time, you're more tired, etc.
2) Gender Ideology. This is an interesting example of trying to decouple any kind of causal link between household labor and sexual frequency by finding a "hidden" third factor that might explain the appearance of any relationship. To quote:
Because women with more traditional attitudes spend more time on housework, they would have less time for sex. Alternatively, women who are traditional might have more sex because they believe it is part of their marital duties
In other words, the key factor here is "traditional attitudes" rather than any direct link between work and sex.
3) Multiple spheres. The idea here is that some people "find time for multiple activities both inside and outside the home." If they're highly-organized at work, this might also apply to home life so that people who work in this "multiple spheres" mode basically make time to schedule in marital sex the same way they would organize time to get work done, etc.
So what were their findings? Let's first go over some worthwhile stats:
- The average married couple in their study had sex 83 times a year, or a little over 1.5 times a week.
- Wives spend about 1.8 times more hours per week on housework than husbands (42 hrs vs. 23.5).
- Their study also validated the reality of the Second Shift...but not as much as one might think. Though men spend more time doing paid work then women, when you add up the total number of hours of work (whether pair or unpaid), women spend 4 more hours a week working than men do (61.4 hours a week for women vs. 57.1 for men).
- A few findings they came across not directly related to their core thesis but still worth mentioning: Protestant couples have sex more than Catholic ones, wives with college degrees report lower sexual frequency but couples with higher incomes report higher frequency, and Black couples reported higher frequency than White couples.
And here's the payoff in regards to their study:
The results also show a significant positive association between hours spent on household tasks and sexual frequency. For both men and women, greater time spent doing household labor is associated with higher sexual frequency... A 1% increase in wives' weekly hours on housework is associated with a 0.11% increase in yearly sexual frequency. For men...a 1% increase in husbands' weekly hours in housework results in a 0.06% increase in the couple's yearly sexual frequency.
To put this in more concrete terms, Gager/Yabiku provide this example, comparing two different couples:
[With] the first couple, the wife does 16 hr and the husband does 2 hr of housework (a week). In the second couple, the wife does 68 hr and the husband does 45 hr. The difference in predicted yearly sexual frequency between these couples is 15 times--or about 1.3 additional times per month for the second couple.
Not only do these findings contradict the assumptions of the "Time Availability" hypothesis but they also tested it against the "traditional attitudes" thesis (i.e. Gender Ideology) and found that the same work/sex relationship held regardless if the couples involved self-identified as having more "traditional" values or not.