@article{111,
  author = {Asim Khwaja and Tahir Andrabi and Jishnu Das and Tristan Zajonc},
  title = {Do Value-Added Estimates Add Value? Accounting for Learning Dynamics},
  abstract = {This paper illustrates the central role of persistence in estimating and interpreting value-added models of learning. Using data from Pakistani public and private schools, we apply dynamic panel methods that address three key empirical challenges: imperfect persistence, unobserved heterogeneity, and measurement error. Our estimates suggest that only one-fifth to one-half of learning persists between grades and that private schools increase average achievement by 0.25 standard deviations each year. In contrast, value-added models that assume perfect persistence yield severely downward estimates of the private school effect. Models that ignore unobserved heterogeneity or measurement error produce biased estimates of persistence.},
  year = {2011},
  journal = {American Economic Journal of Applied Economics},
  volume = {3},
  pages = {29-54},
}