The development of a bridging social capital questionnaire for use in population health research

Bridging social capital is defined as the connections between individuals who are dissimilar with respect to socioeconomic and other characteristics. There is an important gap in the literature related to its measurement. We describe the development and validation of a questionnaire to measure bridging social capital. We focused the development of the questionnaire to be suitable for use in Latino immigrant populations in the U.S. The structure of the questionnaire comprised the following: Socialization in the job place (5 items); Membership in community activities (16 items); Participation in community activities (5 items); Contact with similar/different people (7 items); Assistance (17 items); Trust of institutions, corporations and other people(14 items); and Trust of intimate people (3 items). First, we used focus groups (N=17 participants) to establish content validity with an inductive thematic analysis to identify themes and subthemes. Changes were made to the questionnaire based on difficulty, redundancy, length and semantic equivalence. Second, we analyzed the questionnaire's psychometric properties (N=138). We tested internal consistency with Cronbach alpha and construct validity with a Confirmatory Factor Analysis (CFA) for each sub-scale to test theoretical unity; discriminant validity to observe differences between participants from high and low SES backgrounds and different language; and content validity with an independent expert panel. Cronbach alphas ranged from 0.80 (Assistance) to 0.92 (Trust). CFA results indicated that CFI and TLI were higher than 0.90 in almost all the scales, with high factor loadings. The Wilcoxon tests indicated that there were statistically significant mean differences between SES and language groups (p<0.00). The independent expert panel determined that the questionnaire had good content validity. This is the first demonstration of a psychometrically validated questionnaire to measure bridging social capital in an immigrant population in the United States. Our questionnaire may be suitable for further refinement and adaptation to other immigrant groups in different countries.