The seasonal job surge

Casey Mulligan has a provocative piece in the NY Times (here, here). He shows that teenage employment surges in the summer when school lets out as shown in the graph below. This isn't really an astounding finding, but it does seem to imply that a shock to labor supply (the school year ends, making kids available for employment) can affect employment even in the middle of a severe recession. This implies that if government efforts to stimulate demand come with impediments to labor supply they may end up being ineffective or counterproductive. Mulligan makes exactly this claim about ARRA, though what these restrictions are isn't exactly clear.

The argument is interesting, but there's an obvious demand-side explanation for the surge in teen employment during the summer. Summer brings demand for lifeguards, amusement park ride operators, lawn care workers, house painters and other types of jobs typically taken by teenagers. Mulligan's a smart guy, surely he could figure out how much of the surge is due to the opening up of this type of employment in the summer months and how much is due to the release of workers.

[Note: Ryan Avent makes the same argument as me here, with some data.]