Andrabi, Tahir, Jishnu Das, Asim Ijaz Khwaja, and Tristan Zajonc. "Here Today, Gone Tomorrow? Examining the Extent and Implications of Low Persistence in Child Learning." HKS Faculty Research Working Paper Series RWP09-001, January 2009.
Learning persistence plays a central role in models of skill formation, estimates of education production functions, and evaluations of educational programs. In non-experimental settings, estimated impacts of educational inputs can be highly sensitive to correctly specifying persistence when inputs are correlated with baseline achievement. While less of a concern in experimental settings, persistence still links short-run treatment effects to long-run impacts. We study learning persistence using dynamic panel methods that account for two key empirical challenges: unobserved student-level heterogeneity in learning and measurement error in test scores. Our estimates, based on detailed primary panel data from Pakistan, suggest that only a fifth to a half of achievement persists between grades. Using private schools as an example, we show that incorrectly assuming high persistence significantly understates and occasionally yields the wrong sign for private schools' impact on achievement. Towards an economic interpretation of low persistence, we use question-level exam responses as well as household expenditure and time-use data to explore whether psychometric testing issues, behavioral responses, or forgetting contribute to low persistence--causes that have different welfare implications.