Randomization is one of the most persuasive techniques for determining cause and effect. Half of a certain group get a treatment; half don't. Compare. If the groups were truly chosen at random, and the treatment was truly the only difference between them, and the differences in outcomes are meaningful and the size of the samples are also large enough for drawing statistically meaningful conclusions, then the differences can tell you something about causes.
It’s not unusual to hear predictions that in the future, we will all have opportunities to run our own companies, or that jobs will become a series of freelance contracts. Here’s a representative comment from business school professor Arun Sundararajan (“The Future of Work,” Finance & Development, June 2017, p. 7-11):
What if countries could have some built-in flexibility in repaying their debts: specifically, what if the repayment of the debt was linked to whether the domestic economy was growing? Thus, the burden of debt payments would fall in a recession, which is when government sees tax revenues fall and social expenditures rise. Imagine, for example, how the the situation of Greece with government debt would have been different if the country's lousy economic performance had automatically restructured its debt burden in away that reduced current payments. Of course, the tradeoff is that when the economy is going well, debt payments are higher -- but presumably also easier to bear.
There's a lot of talk about the opioid crisis, but I'm not confident that most people have internalized just how awful it is. To set the stage, here are a couple of figures from the 2018 Economic Report of the President.
Public programs for pre-K education have a worthy goal: reducing the gaps in educational achievement that manifest themselves in early grades. I find myself rooting for such programs to succeed. But there are now two major randomized control trial studies looking at the the results of publicly provided pre-K programs, and neither one finds lasting success. Mark W. Lipsey, Dale C. Farran, and Kelley Durkin report the results of the most recent study in "Effects of the Tennessee Prekindergarten Program on children’s achievement and behavior through third grade" (Early Childhood Research Quarterly, 2018, online version April 21, 2018).
Weakness in Copper persists, and it shows the risks to optimistic global growth and inflation expectations. But something else is happening in gold and copper apart from global slowdown and US dollar strength.
The cause seemed worthy, and the policy mild. Militia groups in the Democratic Republic of the Congo (DRC) were taxing and extorting revenue from those who mined like tin, tungsten, and tantalum. Thus, Section 1502 of the Dodd-Frank Act of 2010 required companies to disclose the source of their purchases of such minerals. The hope was to reduce funding for the militias, and thus to benefit people in the area. Human rights advocacy groups supported the idea. The Good Intentions Paving Company was up and running.