Economists compared fast-food jobs across a state border to test a textbook prediction

Standard economic theory predicted a higher minimum wage would cut jobs. In 1994, David Card and Alan Krueger compared fast-food employment in New Jersey, which raised its minimum wage, against neighboring Pennsylvania, which didn't. Employment in New Jersey didn't fall — it rose slightly relative to Pennsylvania, a result that reignited decades of debate among economists.

— David Card and Alan Krueger, Minimum Wages and Employment: A Case Study of the Fast-Food Industry in New Jersey and Pennsylvania — American Economic Review, 1994