This is one of the first books to provide a textbook exposition of the literature on how to measure accurately the 'effects' of a 'treatment,' such as a drug, educational program, or tax regime, on a response variable like an illness, GPA, or income. The book focuses on non-experimental, micro-economic estimation. About the SeriesAdvanced Texts in Econometrics is a distinguished and rapidly expanding series in which leading econometricians assess recent developments in such areas as stochastic probability, panel and time series data analysis, modeling, and cointegration. In both hardback and affordable paperback, each volume explains the nature and applicability of a topic in greater depth than possible in introductory textbooks or single journal articles. Each definitive work is formatted to be as accessible and convenient for those who are not familiar with the detailed primary literature.