A simple modification of the Bhagavantam–Venkatarayudu method is used to calculate the contribution of each atom in a unit cell to a representation of the factor group. Results have been computed for all sites in all 230 space groups, but only a few are given here in illustration of the method. The use of these data is illustrated for ionic, complex ionic, and molecular crystals as well as for polymers and layer structures. By its nature the method also yields the results of equivalent analyses for 32 of the point groups.