Regarding the 30% tenure rate, it turns out the key words are “at their first jobs.” This analysis compared people who got tenure at their first job to everybody else — which means that leaving for a better outside offer is treated the same in this analysis as being denied tenure. So the tenure-at-first-job variable is not a clear indicator of whether the policy is helping or hurting a career. What if you look at the effect of the policy on getting tenure anywhere? The authors did that, and they summarize the analysis succinctly: “We find no evidence that gender-neutral tenure clock stopping policies reduce the fraction of women who ultimately get tenure somewhere” (p. 4). That seems pretty important. What about that swing from gender-neutral to a 6-to-1 disparity in the at-first-job analysis? Consider this: “There are relatively few women hired at each university during the sample period. On average, only four female assistant professors were hired at each university between 1985 and 2004, compared to 17 male assistant professors” (p. 17). That was a stop-right-there moment for me: if you are an economics department worried about gender equality, maybe instead of rethinking tenure extensions you should be looking at your damn hiring practices. But as far as the present study goes, there are n = 62 women at institutions that never adopted gender-neutral tenure extension policies, and n = 129 at institutions that did. (It’s even worse than that because only a fraction of them are relevant for estimating the policy effect; more on that below). With a small sample there is going to be a lot of uncertainty in the estimates under the best of conditions. And it’s not the best of conditions: Within the comparison group (the departments that never adopted a tenure extension policy), there are big, differential changes in men’s and women’s tenure rates over the study period (1985 to 2004): Over time, men’s tenure rate drops by about 25%, and women’s tenure rate doubles from 12% to 25%. Any observed effect of a department adopting a tenure-extension policy is going to have to be estimated in comparison to that noisy, moving target.

Source: Don’t change your family-friendly tenure extension policy just yet – The Hardest Science