A punched card procedure for a general weighted least squares solution to successive intervals is described. Use of zero weights permits application of this procedure to cases of incomplete data. The procedure outlined suggests use of an IBM Type 101 statistical sorter for obtaining frequency counts. Conversion of frequencies to normal curve deviates and assignment of weights is accomplished on a gang punch. The main procedure is an iterative process with repetitive cycles of computation using a calculating punch, Type 602-A, and a tabulator. A numerical example is given to illustrate the machine sequences. The example employs data collected by Saffir (8). The resulting scale values and discriminal dispersions are approximately linearly related to corresponding values found by Saffir (8) and Gulliksen (6).