Cover Story: REI Treks Ahead

Score Everyone Twice
The company then scored everyone on the file twice using the mailed and no-mailed group models. Subtracting the no-mail score from the mailed score leaves the incremental, or difference, score. REI sorts by this score and mails the best incremental customers.

The incremental model is designed to identify the customers most likely to be influenced by the catalog. “Usually the coefficients on the variables are different,” Bowcut notes, “but the variables are the same: dominated by RFM, category, seasonal-type variables.”