A function h (hierarchy index) is presented of a sociometric matrix in which each member of a group ranks all other members according to some characteristic. The value of h ranges from 0 when the members of the group are indicated by the data to be equal with respect to the characteristic in question, to 1 when the most extreme type of hierarchical relationship appears. Differences between the h values obtained from 2 sets of observations, whether from the same group or from different groups, may be tested for significance. A coefficient of agreement theta is introduced as another method of comparing the group structures associated with 2 sets of data from groups of the same size. The coefficient theta ranges from -1 when the data display opposite hierarchical characteristics, to +1 when they display the same hierarchical characteristics. The measures and h appeared to be of considerable sensitivity.