Applied econometrics, known to experts as Metrics, is the original data science. Metrics encompasses the statistical methods that economists use to untangle cause and effect in human affairs. Through accessible discussions and with a touch of kung-fu-inspired humor, "Mastering Metrics" presents the essential tools of econometric research and demonstrates why econometrics is exciting and useful. The five most valuable econometric methods, or as the authors call them, the Furious Five – randomized assignment, regression, instrumental variables, regression discontinuity designs, and differences in differences – are illustrated through well-designed real-world examples. Does health insurance make people healthier? Randomized experiments provide answers. Are expensive private colleges and selective public high schools better than less prestigious institutions?.