RegressIt: free Excel add-in for regression analysis

Regression Analysis forum members:
I'd like to announce the release of a free Excel add-in for regression and multivariate data analysis which is available at this address: It was developed in a teaching environment but is also intended for serious applied work as a complement or substitute for other regression software. What it does is very basic--descriptive analysis and ordinary linear regression--but for those who use or teach this sort of analysis in an Excel environment, it offers some distinctive features. It draws better-quality scatterplot matrices than you will find just about anywhere else, it draws parallel time series plots of many variables, it provides a lot of well-formatted table and chart output for regression models (all of it in native Excel format), it allows you to easily apply nonlinear and time transformations to variables in a systematic way, and it has a number of audit trail features (date/time/username stamps on all worksheets, unique model names in all table and chart titles, and an additional worksheet with side-by-side comparisons of models) that help to organize and authenticate the results of fitting a sequence of different models to the same data set. I hope it will be of interest to those of you who work with linear regression models and use Excel to some extent or who have colleagues or students who do. This is strictly a public service, non-commercial venture.

--Bob Nau, Duke University