A set of weighting factors on student credit hour production by discipline was developed so that instructional productivity could be equitably compared across disparate disciplines and within disciplines. The new statistical methodology was applied to 3 years of teaching load data from 21 major public universities (the Southern University Group Teaching Load Data Exchange) and has yielded an objective, broadly applicable set of student credit hours (SCH) weight factors. For each fall term from 1978 through 1980, participants reported on the instructional productivity of each of their academic departments. Data included: the standard federal code associated with the department's dominant instructional program; the number of filled instructional full-time-equivalent (FTE) positions, reported as ranked faculty and other faculty (primarily graduate assistants); and student credit hours produced by the faculty, reported by three levels of instruction (lower and upper division undergraduate, and graduate levels). A table of optimum weighting factors for upper division and graduate SCH (relative to lower division) is presented by the code discipline division of the National Center for Education Statistics. The weights derived from the analysis are compared with those developed by more traditional means. An explanation and example of the method are provided, and it is concluded that the number of discipline areas that responded well to the optimum weight model lends support for its acceptance. There was less confidence in the optimum weights for those discipline areas in which only ranked faculty FTE were included in the instructional productivity ratios, since they differ consistently from other reported values. (SW)