One-third hypothesis
The one-third hypothesis (OTH) is a sociodynamic theory asserting that a subgroup's prominence increases as it approaches one-third of the total population and diminishes after it exceeds that number. It was first stated by sociologist Hugo O. Engelmann in a letter to the American Sociologist in 1967: "...we would expect that the most persistent subgroups in any group would be those which approximate one-third or, by similar reasoning, a multiple of [i.e., a power of] one-third of the total group.