Researchers are again comparing married and single people, and declaring married people the winners. I looked at the original research report, as I always do, and found that, as usual, the supposedly magical powers of marriage have been grossly exaggerated. In fact, one consistent set of findings point to marriage as a risk factor.
The same lame methodological mess
This time, the researchers, Natasha Wood and her colleagues, measured the grip strength of people 50 and older in the US and England, and the walking speed of people 65 and older, again in the US and England. Even though the two studies were longitudinal (the same people were followed over time), the authors did not look at how grip strength or walking speed changed as people got married or remarried or divorced or widowed. They just compared the various categories – married, remarried, divorced (or separated), widowed, or never married, separately for men and women.
Maybe you already know what that means: Even if there were differences favoring the married people, that would not necessarily mean that the married people were doing better because they were married. The married people might differ from the unmarried people in all sorts of ways, and maybe that’s why the married people did better. For example, married people are massively advantaged financially, in no small part because of laws that unfairly favor them, so maybe what really matters is who has more money, not who has a marriage certificate. To their credit, the authors did look into that and it did matter. That’s not what you will see in any of the media headlines, though.
Setting aside the weak methodology, did the study show that the single people just aren’t as strong as married people, as some headlines suggested?
To make the case from these two studies that single people are slow-walking weaklings, relative to married people, the authors should show that the never married people have less strong grips and slower walking speeds in both countries, and that the differences aren’t just because the single people have less money.
Spoiler alert! That’s not what happened.
Lifelong single women
Let’s start with the women and their grip strength. The grip strength of the lifelong single women is not significantly different from that of the married women. It is no different in England and it is no different in the US. There’s just no there, there.
What about lifelong single women and their walking speed? In the US, there was no significant difference in the walking speed of the never-married women and the married women. None. In England, the married women walked faster than the never-married women, in the analyses that ignored important ways that the two groups might differ. In analyses that compared married women to never-married women who were similar in important ways, such as their wealth or lack thereof, there was no significant difference in how quickly they walked.
To summarize so far: The married women were no stronger than the women who had never been married. And the married women did not walk any faster than the never-married women, either, when the two groups were similar in important ways, such as wealth.
The divorced women had grips that were less strong than the married women in both countries. But in both countries, that difference disappeared once divorced women were compared to married women who were similar to them in important ways, such as their wealth.
The results were the same for walking speed. If you just compare divorced women to married woman, ignoring the fact that the two groups differ in important ways, then the divorced women walk more slowly. But if you compare divorced and married women who are similar in important ways, such as their wealth, then there are no significant differences in how quickly they walk.
The widowed women had grips that were not as strong as the married women – but only in the US. In England, there were no statistically significant differences.
The widowed women walked more slowly than the married women in both countries – but only if you ignored the other ways the groups differed. When the researchers compared widowed and married women who were similar in important ways, such as their wealth, then, again, there were no significant differences in how quickly they walked.
Lifelong single men
In the US, the married men had stronger grips than the never-married men. But the results did not replicate across countries. There was no significant difference in strength between the married men and the never-married men in England.
The results were inconsistent for walking speed, too, but this time the countries flipped. In the US, the married men did not walk any faster than the never married men. They did walk faster in England.
The married men did not have any stronger grips than the divorced men in the US or in England.
The divorced men did walk more slowly than the married men in both the US and England – but only if you ignore the ways in which the two groups differ. When the researchers compared divorced and married men who were similar in important ways, such as their wealth, then the married men were not any faster.
In the US, the married men had stronger grips than the widowed men. In England, they did, too, but only when important differences between the groups were ignored. When the researchers compared widowed and married men in England who were similar in important ways, such as their wealth, the two groups were no different in their walking speed.
The widowed men walked more slowly than the married men in both countries. Wealth did not account for the differences.
Conclusion: Here’s Your One Table Scrap
Is there a way in which married women or married men are doing better than unmarried women or men, in grip strength or walking speed, that is the same across both countries and cannot be explained by differences in other important factors such as wealth?
Yes. There is one consistent finding. The widowed men walk more slowly than the married men in the US and in England. Taking factors such as wealth into account does not change the findings.
Guess what all widowed men have in common? They were once married. So please, stop telling me that marriage has some magical powers that make people stronger and faster.
UPDATE: After I published this, readers in online forums started wondering why the researchers were studying such weird and specific things such as grip strength and walking speed. Good question! I wrote about that here.