DIVERSITY OF IDEAS ABOUT DIVERSITY MEASUREMENT

Measurement of diversity is important in several sciences but has evol ved mainly within ecology. An ecological community with many species i s more diverse than one with few but the way the total number of indiv iduals is distributed among the species also influences the degree of diversity or heterogeneity. Although not always explicitly used, it ca n be shown that diversity is a concept of some importance in psycholog y, too. In general terms quantification of diversity is related to the apportionment of some quantity into a number of well-defined classes. The dual-concept type of diversity index reflects both the number of classes and the degree of evenness (homogeneity) of the apportionment. The quantity that is distributed has commonly been a population of el ements and apportionment homogeneity measures population heterogencity . The statistical context has dominated the thinking about the measure ment of diversity, heterogeneity, and homogeneity. Some well-known ind ices of diversity and the ideas behind them are discussed. It is concl uded that the general geometric representation of homogeneity (similar ity) and heterogeneity (dissimilarity) (Junge, 1978; !991) offers a mo re general approach to the measurement of diversity.