Murdock's taxonomy encoded the economic, social, and political features of more than 1,100 societies that ethnologists had studied up until that time. In many cases, these codes formed scales – for example, the one concerning the number of levels of political authority outside the local community, from 0 among hunters, to 4 for irrigation empires. Lomax and Arensberg arranged the codes into scales in order to measure the kinds of behaviors of features of culture, such as levels of production or permanence of settlement. When they added factors of expressive communication to the Murdock measures of social relations it produced a geographical taxonomy of human culture.