This document discusses socio-metric scales, which are used to measure social relationships within groups. It defines socio-metry as the quantitative study and measurement of interpersonal preferences. Socio-metric data can be presented as socio-grams (maps of social networks) or socio-matrices (tables showing each person's preferences). It also describes socio-metric indices which reduce social data to numerical values for comparison. The document outlines principles for selecting criteria for socio-metric measurements and discusses advantages and disadvantages of the socio-gram method.