Pub. date: 2011 | Online Pub. Date: October 04, 2011 | DOI: 10.4135/9781412994163 | Print ISBN: 9781412959636 | Online ISBN: 9781412994163| Publisher:SAGE Publications, Inc.About this encyclopedia
Saundra K. Schneider & William G. Jacoby
Regression analysis is, by far, the most commonly used statistical technique in political science. While regression analysis can be defined in many different ways, it is a tool for describing the relationships among variables. Regression is generally used for two complementary purposes. First, it measures the effects of one or more independent variables on a single dependent variable. Second, it can be used to predict the values of a dependent variable that can be expected to occur at specified levels of the independent variables. In the former capacity, regression is a useful tool for theory testing. In the latter capacity, regression is a forecasting tool that is useful for decision making. These two uses are closely connected. Theories are evaluated by their ability to predict as yet unobserved phenomena, and forecasting is carried out most effectively when predictions are based on a substantive theory. In the following, the major features ...