A recent example publicized in the Economist* concerns a correlation between men having children and their being happy, which the Economist (and I think the researcher) simply assume reflects a causal relationship: having children causes happiness.
But when you think about it, it's also quite possible that happy men are more likely to attract women and sire children than unhappy ones, or that men who especially like children are more likely to have them than other men.
The article would have been much ore interesting and informative if the author had mentioned these possibilities. By leaving them unstated, the author very likely misleads most readers into thinking the research demonstrated that having children increases happiness in fathers.
* "The joys of parenthood: Father’s day," May 19, 2012
* "The joys of parenthood: Father’s day," May 19, 2012
It is certainly fair to criticize the Economist article
ReplyDeletehttp://www.economist.com/node/21555543
but don't be too hasty to fault the researcher
http://www.faculty.ucr.edu/~sonja/papers/NKEDLinpress.pdf
Her paper is entitled "In Defense of Parenthood: Children Are Associated With More Joy Than Misery". It uses the proper phrase "associated with" in describing the correlation. Further, the abstract shows that she made no attempt to imply causality:
"Recent scholarly and media accounts paint a portrait of unhappy parents who find remarkably little joy in taking care of their children, but the scientific basis for these claims remains inconclusive. In three studies, we used a strategy of converging evidence to test whether parents evaluate their lives more positively than do non-parents (Study 1), feel relatively better than non-parents on a day-to-day basis (Study 2), and experience more positive feelings during childcare than other daily activities (Study 3). The results indicate that, contrary to previous
reports, parents (and especially fathers) report relatively higher levels of happiness, positive emotion, and meaning in life."
She was clearly aware of the possibility of selection bias "...happier people may be more likely to become parents" (page 11). She tried to test for this in Study 3 which studied parents only.
The final paragraph of the paper (page 15) also speaks to scientific honesty:
"Although it is impossible to randomly assign people to become parents, thereby precluding causal inferences, we believe the present findings may be revealing to the general public, especially for those planning a family. Contrary to repeated scholarly and media pronouncements, people may find solace that parenthood and childcare may actually be linked to feelings of happiness and meaning in life."
Thanks for digging further than I did. I apologize to the researcher and promise to be more careful in the future.
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