Travis Kalanick, the Uber founder, has set up a fund to invest in companies involved in "large-scale job creation." That would seem to be right up his alley: Uber has created lots of jobs. The question, though, is whether they are the kind of jobs that benefit society or, in the final analysis, their holders. A recent academic argument advances the search for an answer to this question.

The Center for Automotive Research at Stanford released a paper last week suggesting that Uber and Lyft drivers in the U.S. made $3.37 an hour. Dragging down their wages in the estimate was work-related expenses like wear-and-tear on the vehicle and fuel. Some 30 percent actually lost money driving for the "gig economy" companies, while 74 percent of drivers made less than the minimum wage in their state.