# Data Analysis for Politics and Policy (eBook)

“Edward R. Tufte’s book *Data Analysis for Politics and Policy* is, quite simply, excellent. The aims of the author in the writing of this book is ‘. . . to present fundamental material not found in statistics books, and in particular, to show techniques of quantitative analysis in action on problems of politics and policy.’ To achieve this end, Tufte considers a narrow range of important topics in statistical analysis, primarily dealing with problems of prediction (including a good discussion of the concept of causation) and the relationships among variables through simple and multiple regression.

The bulk of the book concerns the use and interpretation of simple and multiple regression. Here, the discussion centers on issues that, as Tufte claims, do not usually find a place in standard statistics texts. For example, in simple regression, the book stresses the central role of residuals and residual analysis, and describes many of the measures familiar to social scientists as functions of the residuals, ‘… since reasonable measures of the quality of a line’s fit to the data could hardly be anything but a function of the magnitudes of the errors.’ Tufte puts residual plots to good use to gain understanding of a data set, and he shows how finding outliers gives the analyst hints about the inadequacy of a statistical model. This attitude is clearly passed along to the reader. The discussion of graphical techniques in general is quite good and includes the reproduction of graphs of several scatter plots.

Other topics in simple regression are also considered. A brief but compelling discussion of the `value of data as evidence,’ with regard to the interpretation of nonrandom samples, is presented. An important discussion of the usefulness of computing slopes instead of correlation coefficients is given, complete with a good quote from John Tukey. Several examples requiring transformations of one or both variables to the logarithmic scale are given, along with an interpretation of transformed variables. The section on transformations is difficult for many students, but it contains information that is not usually available to the beginning nontechnical student.

For the last two years, I have used *Data Analysis for Politics and Policy* as a supplemental text in a demanding statistics service course for first year social science graduate students. The book has received almost uniform praise from the students.”

Sanford Weisberg, “Review of *Data Analysis for Politics and Policy*,” *Journal of the American Statistical Association* (September 1976), 768. 179 pages.