Building Multiple Regression Models Interactively

Automated multiple regression model-building techniques often hide important aspects of data from the data analyst. Such features as nonlinearity, collinearity, outliers, and points with high leverage can profoundly affect automated analyses, yet remain undetected. An alternative technique uses interactive computing and exploratory methods to discover unexpected features of the data. One important advantage of this approach is that the data analyst can use knowledge of the subject matter in the resolution of difficulties. The methods are illustrated with reanalyses of the two data sets used by Hocking (1976, Biometrics 32, 1-44) to illustrate the use of automated regression methods.