The method of instrumental variables was first used in the 1920s to estimate supply and demand elasticities, and later used to correct for measurement error in single-equation models. Recently, instrumental variables have been widely used to reduce bias from omitted variables in estimates of...

"In many countries, college-bound high school seniors must pass a test or series of tests. In Israel, this requirement is known as the "Bagrut", or matriculation certificate, obtained by passing a series of subject tests. In spite of the Bagrut's value, Israeli society is marked by vast...