Numerous studies have found that men who are married tend to live longer, healthier lives than do single men. A new study says that married men have another advantage: They are more likely to finish their Ph.D. programs.

Married men finish their doctorates, on average, 0.43 years (or about 5 months) sooner than do single men, according to a study released by the Cornell Higher Education Research Institute. The study also found that married men have attrition rates in graduate programs that are 4.7 percentage points lower than those for single men in each year of their graduate programs.

The study found no significant differences among single students and only marginal gains for married female graduate students. They tend to finish their Ph.D.'s 0.14 years more quickly than single women.

Joseph Price, a graduate student at Cornell, writes in his study that there have been numerous projects examining the impact of gender on graduate student success. But many data sets on graduate students do not have marital status attached to individual files, so it has been difficult to measure the impact of marital status and gender.

Price was able to do his study because of data collected for the Andrew W. Mellon Foundation's Graduate Education Initiative. The foundation supported a number of efforts to improve graduate education and so collected extensive data on demographics and also on degree completion throughout the 1990s. That data come from 10 departments at 10 research universities.

He writes that the likely explanation for the marriage advantage to men is similar to the explanations for why marriage helps men generally. Married men tend to be more productive (across professions), stay in better physical and mental health, and are less likely to engage in "risky behaviors," Price writes. Women are more likely to work hard and avoid risky behaviors than men, regardless of marital status, so marriage doesn't change the equation for them very much.

Price, a Ph.D. student in economics, is married. And he says that his own own experience (and those of his married friends) match his study's findings.