All discussions of interface design criteria emphasize the importance of consistent operating procedures both within and across applications. This paper presents a model for positive transfer and thus a theoretical definition of consistency. An experiment manipulating training orders for utility tasks was designed to evaluate the transfer model. The experimental manipulations produced large transfer effects. Quantitative predictions were derived from the Kieras and Polson (1985) theory of human-computer interaction and the transfer model and fit using regression techniques. The transfer model accounted for 88% of the variance of the 31 cell means.