This course offers an introduction to the understanding of politics through data analysis, with particular emphasis on surveys of the mass public. We will study selecting a sample, designing and conducting a survey, interpreting the results of a survey, correcting for bias in a survey, and measuring the accuracy of a survey. This semester, we will pay special attention to the accuracy of public opinion polling preceding the 2008 primary and Presidential elections. PSC 203 satisfies the Techniques of Analysis requirement for undergraduate majors and minors in political science.