THE RELIABILITY OF NETWORK DENSITY AND COMPOSITION MEASURES

Many measures based on egocentric network data, such as age compositio n or (local) network density, can be viewed as 'aggregate' measures: t hey are mean values of the alter attributes or the dyadic attributes t hat fall within a given respondent's egocentric network. Internal cons istency methods of classical test theory are not suitable for assessin g the reliability of such measures: such methods presume a 'crossed' d esign for data collection in which each respondent is scored on the sa me set of indicators. In designs for gathering egocentric network data , alters are instead 'nested' within respondents; moreover the number of alters may differ across respondents. This paper evaluates the reli ability of composition and density measures via analysis-of-variance a pproaches to reliability known as generalizability theory. Reliability estimates are presented for egocentric measures based on the 1985, 19 87, and 1988 General Social Surveys and for the 1977-1978 Northern Cal ifornia Community Study. Ethnoreligious composition, political composi tion, density, and composition of a network by 'friends' or co-members of organizations are measured with relatively high reliability, even for a relatively small number of alters. Other measures require more a lters to attain adequate reliability, and some, such as sex compositio n, remain problematic even when the number of alters grows quite large . The sensitivity of reliability estimates to differences in instrumen t design is examined using design variations in the surveys studied.