Governments use policy experiments to facilitate learning, but the nature and effects of these experiments remain unclear. We analyze China's policy experimentation since 1980—among the most systematic in history—and document three facts. First, most experiments exhibit positive sample selection. Second, local politicians exert excessive efforts during experiments that are not replicable during policies’ national rollout. Third, the central government is not fully sophisticated when interpreting experimentation outcomes. These facts suggest that policy learning may be biased and national policies may be distorted. Thus, while China’s institutions enable experimentation at an unparalleled scale, the complex political environments can also limit effective policy learning.

We study the causal effect of school curricula on students? political attitudes, exploiting a major textbook reform in China between 2004 and 2010. The sharp, staggered introduction of the new curriculum across provinces allows us to identify its causal effects. We examine government documents articulating desired consequences of the reform and identify changes in textbooks reflecting these aims. A survey we conducted reveals that the reform was often successful in shaping attitudes, while evidence on behavior is mixed. Studying the new curriculum led to more positive views of China?s governance, changed views on democracy, and increased skepticism toward free markets.