This paper presents a new approach to the measurement of change within human systems (individuals, groups, organizations, communities). It is reported as being a more realistic and accurate approach than the use of simple raw-score change, easier to calculate than the analysis of co-variance and other procedures designed to equalize the effects of individual difference in pre-scores, and more able to provide meaningful comparisons between cases. The approach is called "percentage gain" and is computed by taking the percentage that the actual raw score point change is, of the number of points available between the pre-score and the highest possible scores. Percentage gain scores were calculated for a sample of 196 workshop students and compared with simple raw change scores in several statistical analyses. (Author)