Below I've turned the odds ratios of the Belgian Tinder study into percentages and also risk ratios, because I do not find odds ratios very intuitive. I've also added confidence intervals because any statistics are pretty meaningless without confidence intervals (unless you have lots of experience what to expect for different sample sizes).

Link to study: https://www.reddit.com/r/BlackPillScience/comments/bl41up/based_on_selfreports_by_1038_belgian_tinder_users/

The key formulas are:

  • Odds ratio: OR = (EE / EN) / (CE / CN)
  • Risk ratio: RR = percentage females / percentage males = (EE / (EE + EN)) / (CE / (CE + CN))

In case of the Tinder study, experimental group (E) to females, and control group (C) to males, event (E) refers to some behavior like engaging in casual sex, and (N) to not engaging in causal sex. So EE is the number of females who engaged in casual sex. EN those that did not. CE and CN is the same for males.

The study mentioned various interesting ORs in Table 2 in the Exp(B) columns.

OR > 1 favors women, and OR < 1 favors men.

Of the 1038 Belgian Tinder users, 59% were female (639 females, 399 males). 571 (55%) had met a person through Tinder (sex OR 1.28). Of those,

  • 23% had at least one one-night stand, OR 0.72
  • 31% engaged in a casual sexual relationship with another Tinder user, OR 2.72
  • 27% started a committed relationship with another Tinder user, OR 1.27

Based on the numbers above, one can calculate the EEs and CEs like this:

  • OR = (EE / EN) / (CE / CN)
  • EE + EN = 639
  • CE + CN = 399
  • EE + EN + CE + CN = 1038 * percentage from above

Resulting table with 95% confidence intervals:

Behavior % EE EN CE CN % females % males OR RR Corrected RR
Met a person 55% 367 272 204 195 57.36 (53.60, 61.27) 51.24 (46.22, 56.03) 1.28 (1.00, 1.65) 1.12 (1.00, 1.26) 1.45 (1.30, 1.61)
One-night stand 13% 72 567 60 339 11.22 (8.82, 13.72) 14.94 (11.53, 18.54) 0.72 (0.50, 1.04) 0.75 (0.55, 1.03) 0.97 (0.72, 1.31)
Casual sexual relationship 18% 140 499 37 362 21.87 (18.70, 25.12) 9.33 (6.43, 12.12) 2.72 (1.85, 4.00) 2.34 (1.67, 3.29) 3.03 (2.18, 4.22)
Committed relationship 15% 102 537 52 347 15.99 (13.12, 18.80) 13.03 (9.73, 16.34) 1.27 (0.89, 1.82) 1.23 (0.90, 1.67) 1.59 (1.18, 2.13)

The last column is corrected for the fact that women underreport their sexual activity by around 1 - 3.4 / 4.4 = 23% in anonymous settings as was found in this study: https://www.jstor.org/stable/3813768

Except for casual sexual relationships, the sex differences are not very large. The OR for one-night stands favors males, as expected since men are much more promiscuous.

Perhaps women lie more about one-night stands because it would be very detrimental to their reputation if other women would know. Lower inequality in romantic relationships confirms stereotypes modern females being unable to settle down to some extent.

Generally, keep in mind that vast inequalities are not even expected as it seems that unfulfilled hypergamous desires rather result in women staying single since monogamy is still being largely enforced.