%0 Journal Article %J American Journal of Preventive Medicine %D 2021 %T Volunteering as an Equalizer: A Quasi-Experimental Study Using Propensity Score Analysis %A Kim, Seoyoun %A Cal J. Halvorsen %K health %K Volunteering %K Wealth %X Formal volunteering in later life is beneficial for both physical and psychological well-being. However, research points to potential selection bias because older adults with key advantages, such as wealth, are more likely to volunteer and reap its benefits. Accordingly, this study addresses this selection bias by considering the characteristics of volunteers and nonvolunteers using the inverse probability of treatment weighting. It also examines whether volunteering has differential impacts between the highest and lowest wealth quintiles using inverse probability of treatment weighting. Methods Data were analyzed from the 2004–2016 waves of the Health and Retirement Study (N=90,881). The weights, created using a machine learning method, were incorporated in the analysis to estimate the treatment effects along with relevant covariates. Analyses were conducted in 2020. Results Volunteering enhanced self-reported health and reduced depressive symptoms in the full sample. Furthermore, those in the lowest wealth quintile experienced significantly better self-reported health from volunteering than their wealthy counterparts. Volunteering was associated with fewer depressive symptoms regardless of wealth status. Conclusions The study enhances the understanding of formal volunteering and health while suggesting that volunteers with low wealth may benefit more from volunteering in terms of their health. Hindrances to volunteering among the least wealthy, such as financial distress, discrimination, or lack of organizational support, may attenuate the benefits of voluntary activity. %B American Journal of Preventive Medicine %V 61 %P 628-635 %G eng %N 5 %R 10.1016/j.amepre.2021.05.004