This monograph reviews studies which have measured and compared classroom and other human behaviors occurring in different cultures and nations, points out problems related to the comparisons made, and describes procedures which can be used to help standardize measurements of behavior made using systematic observation instruments. Standardization is considered to be achieved when behaviors are classified the same way by different observers who use an instrument, and when measurements which result have scalar identity and are free of systematic observation errors. Procedures discussed include using observers from each culture studied, and preserving instrument descriptions, samples of behaviors studied, and associated standard measurements of those behaviors for reference by others. Areas needing additional research and thought are also highlighted. (Author)