Complementarities in Automobile Production

The number of different car and light truck models produced in North America has increased enormously over the last decades. The data suggests that producing this increased variety of vehicles is associated with a productivity penalty. We show that manufacturers can adopt complementary activities to reduce this penalty. Flexible technology, defined as the ability to assemble models derived from different "platforms" on the same assembly line, and bringing previously outsourced activities in-house are two such activities that we identify. Both are costly themselves, in terms of lower productivity, but they reduce the cost of producing greater variety. The results are robust to controlling for the endogeneity of the adoption decisions using activity-specific instruments, as proposed by Athey and Stern (2003).