Research That Matters (January 17 - 20, 2008)

Purpose: This study explores the impact of individuals' bonding and bridging social capital on their long-term economic well-being, with specific attention to poor people. Social capital usually refers to social networks, trust, and norms. Studies in the social work field (e.g., Henly, Danziger, & Offer, 2005) have examined how social networks and social supports contribute to low-income people's economic well-being. Social capital theories also distinguish bonding capital from bridging capital. Bonding capital refers primarily to social interactions between relatives and other close friends, while bridging capital refers to individuals' group memberships. Compared with bonding capital, bridging capital is regarded as critical for community and individual economic well-being.

No previous empirical studies have used nationally representative data to examine if individuals' social capital affects their longitudinal economic well-being, or if bonding and bridging capital function differently in affecting such well-being. This study addresses that gap in the literature.

Method: I use data from the National Survey of Families and Households (NSFH) (1987-1988 & 1992-1994). The sample consists of 5330 non-elderly adults who completed interviews at both waves. Social capital (bonding capital & bridging capital) and control variables are drawn from wave one interviews in 1987-1988. Bonding capital is measured by an index ranging from 0-28 formulated from 7 questions asking about respondents' social interaction frequencies (going out with relatives, friends, etc). Bridging capital is measured by an index ranging from 0-60 formulated from 15 questions concerning respondents' group participation frequencies. This measurement fits the commonly accepted definitions of bonding and bridging capitals well. The dependent variables are individuals' income change between the two waves, as well as their families' income-to-needs ratio in wave two, approximately five years apart from wave one. Natural logarithms are used to address the skew distribution of the dependent variables.

Results: Compared with the non-poor, poor people exhibited slightly lower level of bonding capital (mean=8.9 vs. mean=9.4, p<.05), but much lower bridging capital (mean=3.3 vs. mean=4.5, p<.0001). Controlling for individuals' income, employment status, education, demographic factors and other major economic-well being related factors at wave one, regression analysis indicated that (a) higher bridging capital at wave one was associated with greater income increases between the two waves (standardized beta=.056, p<.001); (b) bridging capital at wave one was positively associated with income-to-needs ratio (ln) at wave two (standardized beta=.048, p<.001). However, the bonding capital was not significantly related to individual economic well-being. These findings are consistent with the theoretical hypothesis suggesting that bridging capital instead of bonding capital has positive effects on individuals' economic well-being.

Conclusions and implications: The findings indicate that (a) compared with the non-poor, poor people are lower in bridging capital, but may not be lower in bonding capital; (b) bridging capital is important for individuals' long-term economic well-being. These findings imply that policies and practical efforts to enhance poor people's community group participation and broader social engagement may be quite meaningful for their long-term economic well-being. This suggests the need for experimentation with community intervention efforts designed for this purpose.