We reassess the evidence for (or against) a key implication of the basic real business cycle model: that aggregate hours worked increase in response to a positive technology shock. Two novel aspects are the scope (14 OECD countries) and the inclusion of data on both labor supply margins to analyze the key margin of adjustment in aggregate hours. The short-run response of aggregate hours to a positive technology shock is remarkably similar across countries, with an impact fall in 13 out of 14 countries. In contrast, its decomposition into intensive and extensive labor supply margins reveals substantial heterogeneity in labor market dynamics across OECD countries. For instance, movements in the intensive margin are the dominant channel of adjustment in aggregate hours in 6 out of 14 countries of our sample, including France and Japan.