Sociometry is a noun that refers to the quantitative study and measurement of relationships within a group of people. 

Stemming from the Latin words socius (SO see oos) meaning ‘companion’ or ‘associate’ and metrum (MET room) meaning ‘measurement,’ our word of the day has been with us since the early 20th century. Here’s an example:

If someone had done a sociometry of our high school football team, they might have been troubled by what they would have found. Some of those guys were so weird their behavior would have puzzled the sociologists of the world.