Instrumental Variables Before and LATEr
  The modern formulation of the instrumental variable methods initiated the valuable interactions between economics and statistics literatures of causal inference and fueled new innovations of the idea. It helped resolving the long-standing confusion that the statisticians used to have on the method, and encouraged the economists to rethink how to make use of instrumental variables in policy analysis. [arXiv:1410.0163] 
Toru Kitagawa
stat.ME