Disparities in sense of community: true race differences or differential item functioning?

The sense of community index (SCI) has been widely used to measure psychological sense of community (SOC). Furthermore, SOC has been found to differ among racial groups. Since different ethnic groups have different cultural and historical experiences that may lead to different interpretations of measurement items, it is important to know whether the instrument used to measure the construct of interest has equivalency in measurement across groups or if the instrument exhibits differential item functioning (DIF). Examining DIF in the SCI helps assure that subgroup comparisons identify true differences in SOC between Blacks and Whites. We did not find DIF between races but we did find that that the SCI question 'I feel at home in my neighborhood' was a more reliable measure of SOC for Whites than for Blacks. In other words, this item has less measurement error for Whites than for Blacks. Therefore, differences on the SCI may be attributable to true differences in SOC between races rather than DIF.