you might worry about a correlation/causation problem with that kind of statement. However, there have also been several twin studies that help eliminate this bias.
There is, however, another worry unaddressed by those studies, which wolajacy raises in their comment. This is the debate between the ‘human capital’ and ‘signaling’ theories of education, covered extensively in Bryan Caplan’s book, The case against education. Even if years of education cause—rather than correlate with—increased quality of life and length of life for individual people, reducing years of education for the population as a whole may not reduce those measures much if signaling is the main causal mechanism.
I don’t think twin studies entirely answer this since genetics isn’t everything. I’ve known several genetically-identical twins and none of them had identical personalities.
Of course genetics isn’t everything. This is recognized in the third law of behavioral genetics. Researchers who rely on twin studies do not assume otherwise.
The post addresses this worry:
There is, however, another worry unaddressed by those studies, which wolajacy raises in their comment. This is the debate between the ‘human capital’ and ‘signaling’ theories of education, covered extensively in Bryan Caplan’s book, The case against education. Even if years of education cause—rather than correlate with—increased quality of life and length of life for individual people, reducing years of education for the population as a whole may not reduce those measures much if signaling is the main causal mechanism.
I don’t think twin studies entirely answer this since genetics isn’t everything. I’ve known several genetically-identical twins and none of them had identical personalities.
Of course genetics isn’t everything. This is recognized in the third law of behavioral genetics. Researchers who rely on twin studies do not assume otherwise.