Traits can be associated not only because they are functionally related, but because they were transmitted together either through cross-cultural borrowing or through descent from a common cultural ancestor.
The number of cultures is large and varied enough to provide a sound basis for statistical analysis; the sample includes 186 cultures, ranging from contemporary hunter gatherers (e.g., the Mbuti), to early historic states (e.g., the Romans), to contemporary industrial peoples (e.g., the Russians) (Silverman & Messinger 1997; Mace & Pagel 1994).
By focusing scholarly attention on this sample of 186 cultures, the data have steadily improved in scope and quality.
The open access electronic journal World Cultures, founded by White, published by William Divale, and now edited by J. Patrick Gray, functions as the repository of the SCCS, archiving the now nearly 2000 coded variables and publishing a number of papers on cross-cultural methodology.
Murdock also founded the Human Relations Area Files (HRAF) at Yale University in the 1940s.