Detectable differences or functional equivalents? Assessing the reliability and validity of two measures of online network diversity

Political communication researchers commonly use one of two strategies to measure online network diversity: a "subjective " approach tapping participants' impressions of the diversity in their networks, or a "structural " approach that asks about the socioeconomic position of individuals within their networks. While these measures are largely treated as functional equivalents in research about information technology and politics, we demonstrate that the two measures are only moderately correlated, and there are systematic differences in the reliability and validity of the two measures. We conclude that the structural measure is the better choice for most studies, although the subjective measure may be more appropriate in some cases.