In America median workers require a 3% higher wage to accept a job than they did before the pandemic, according to a recent survey by the New York Fed. For low-wage workers the necessary wage has gone up 19%.

None of these explanations is fully satisfactory. Britain and Australia are also suffering worker shortages in some industries, despite not having generous unemployment benefits. It seems strange that young waiters, who could be vaccinated should they so choose, would see the restaurants to which consumers are happy to return as too risky to work in. A new paper by Jason Furman and Wilson Powell III of Harvard University and Melissa Kearney of the University of Maryland finds that additional joblessness among mothers of young children accounts for only a “negligible” share of America’s employment deficit, contrary to the conventional wisdom.