The Human Relations Area Files, Inc. (HRAF), located in New Haven, Connecticut, US, is an international nonprofit membership organization with over 500 member institutions in more than 20 countries.
A financially autonomous research agency based at Yale University since 1949, its mission is to promote understanding of cultural diversity and commonality in the past and present.
It is an ever-growing catalogue of cross-indexed ethnographic data, sorted and filed by geographic location and cultural characteristics.
The HRAF Collection of Ethnography (the pre-electronic precursor to eHRAF World Cultures) was originally distributed as paper files.
[4] The HRAF databases were developed to foster comparative research on humans in all their variety, from small-scale hunting and gathering societies to complex states.
Although the HRAF collections can be used for many purposes, they were primarily designed to enable researchers to find information quickly across a broad range of cultures so that societies could be compared on particular dimensions of variation.
Most cross-cultural researchers test hypotheses on worldwide samples with the aim of arriving at valid generalizations about human behavior and social and cultural life.
While passages in ethnographies or archaeological reports are readily found using HRAF's subject-indexing system, there are few pre-coded variables in eHRAF.
It is not difficult, after a little practice, to develop ordinal scales that can allow for the coding of words into quantitative measures, and once that is done it is easy to use available software to test hypotheses, and compare, combine, and model the results.
But for many questions about cultural evolution, the ethnographic (or ethnohistorical) record is not likely to provide enough of the necessary time-series data for statistical analysis.
This dilemma particularly applies to the classical questions about human cultural evolution, including the emergence of agriculture, the rise of social inequality and the first cities, and the origins of the state.
Cross-cultural (comparative ethnographic) studies can provide archaeological indicators of cultural and other (e.g., physical and social environmental) features.
Using those indicators, researchers could test many causal ideas about the major events in cultural evolution and devolution on the time-series data in the archaeological record.