Cultural Resource Analysts, Inc., employs a number of lithic specialists. Lithic specialists use various measures to better analyze the lithic assemblage from a site and create a picture of what life may have looked like for prehistoric people. One such measure used by CRA lithic specialists is Diversity Analysis.
Diversity analysis measures how the number of specimens is distributed among various artifact classes under investigation (see Kintigh 1984, 1989 for further discussion concerning the use of diversity analysis in archaeology). The following two dimensions of diversity are computed: richness, which measures the number of different classes present; and evenness, which measures the uniformity of distribution of relative proportions of the classes (Bobrowsky and Ball 1989; Jones and Leonard 1989; Kintigh 1989).
One application of diversity analysis in archaeology is in the examination of occupation intensity. It is assumed that an increased number of activities would be expected as a location is occupied for longer periods of time (e.g., Jones et. al 1989; Magne 1989; Reid 1982 [cited in Kintigh 1989:31]; Schiffer 1975). This should be evident in the tool classes represented at each location. Even in the case of activities occurring off site, a number of implements would still have been returned to the residential location and deposited. This is especially true of those implements that are hafted (Keeley 1982; Towner and Warburton 1990). Numerous tool classes should represent a long-term occupation, as many activities would likely have taken place. Conversely, few tool classes should represent a short-term occupation. In terms of diversity, long-term occupations should exhibit high richness scores while short-term occupations should exhibit low richness scores. Evenness scores should be within, or greater than, the expected range for that sample size depending on the length of occupation.
For example, a location that served as a seasonal base camp should be within the expected range while a longer-term occupation (several seasons) would likely exhibit a greater than expected evenness score. This is due to the various activities (and the number of different activities) that would be associated with such occupations. Locations that represent limited activity loci should exhibit lower than expected evenness scores. The use of diversity analysis gives an indication of occupation intensity and allows for comparisons between various assemblages. Further examination of the artifact classes represented can be used to infer what activities these assemblages represent.