北大计量经济学讲义-第一讲.ppt

INTERMEDIATE ECONOMETRICS Economics Double Major Yan Shen, CCER Fall, 2005 Outline What is econometrics What can econometrics do for us Data: The Input Steps in Empirical Analysis What Will be Covered in This Course What is econometrics Ragnar Frisch （1933）: “The (econometric) society... main object shall be to promote studies that aim at a unification of the theoretical-quantitative and empirical-quantitative approach to economic problems that are penetrated by constructive and rigorous thinking similar to that which has come to dominate in the natural sciences.” What is econometrics Econometrics is not just economics statistics, nor economic theory, nor application of mathematics to economics. It is the unification of the three. What can econometrics do for us? Testing economic theories Explain behaviors that are of economic nature Explain behaviors disguised not to be of economic nature Policy evaluation What can econometrics do for us? An Example y=f(x1,x2,x3,x4,x5,x6,,x7) y : hours spent in criminal activity x1 :”wage” of the criminal activity x2,: hourly wage in legal employment x3 : Income other than from crime or employment x4,: Probability of getting caught. x5: Expected sentence if got caught x6,: Age x7: Discrimination degree received in cities What can econometrics do for us? Overall, we use econometrics to explain phenomena of economic nature, make policy recommendations and make forecasts about the future. Data : The Input Cross – Section data A cross-sectional data set consists of a sample of individuals at a given point in time. Here individuals are considered in broader sense. Cross-sectional data are widely used in economics, especially in fields like labor economics, health economics, urban economics, etc. Data : The Input Notice that cross-sectional data can include variables that describes situations in the past or in the future. In this course we will mainly discuss the analysis of cross-sectional data, since its data st