Congressional Republicans and White House officials have argued against extending the weekly $600 unemployment boost, which expired at the end of last month, by claiming that it paid people more than they were making at their jobs. A study released Wednesday suggests that for most Americans, that isn’t true. In June, Larry Kudlow, director of the National Economic Council, called the $600 checks a “disincentive” to work—a word later repeated by several GOP senators and by the president himself.