State Earned Income Tax Credits and Firearm Suicides

Firearm suicides are an increasing public health crisis and disproportionately impact low-income communities. The earned income tax credit (EITC) is the largest poverty alleviation program for working families with low income in the US.

To evaluate the association of presence and generosity of state EITC policies with state-level firearm suicide rates.

This ecological cohort study analyzed EITC data and suicide rates from 46 US states and Washington, DC, from 1981 to 2019. Data analysis was conducted from June 2022 to August 2024.

The exposure was the presence and generosity of state refundable EITCs (ie, amount of a refundable tax credit that exceeds income tax liability is refunded to taxpayers). The EITC generosity was measured as a continuous exposure quantified by percentage of the federal EITC offered by a state each year.

The outcome was state-level annual firearm suicide rates. The association of state EITC implementation with firearm suicide rates was estimated using heterogeneity-robust 2-stage difference-in-difference (DID). All regression models used ordinary least squares, included state and year fixed effects with standard errors clustered at the state level, and adjusted for time-varying state-level covariates.

Individual-level data were not available in this study of state-level firearm suicide rates. During the study period, 20 states implemented a refundable EITC (generosity range, 3.4%-85%). In 2019, the final year of the study, the nationwide rate of firearm suicide was 7.29 per 100 000 persons. A statistically significant negative association was found between refundable EITCs and firearm suicide rates. Every 10% increase in refundable EITC generosity was associated with a decrease in the mean firearm suicide rate by 0.28 (95% CI, -0.48 to -0.08) cases per 100 000 person-years (relative decline, 4.3%; 95% CI, 1.5% to 7.0%). The mean firearm suicide rate was 0.49 (95% CI, -0.91 to -0.07) cases per 100 000 person-years fewer comparing postimplementation and preimplementation years among states that implemented a refundable EITC contrasting with the change during that time in states without a refundable EITC (relative decline, 7.9%; 95% CI, 2.7% to 12.9%).

In this cohort study, the presence and generosity of state refundable EITCs were associated with a decrease in firearm suicide rates, supporting the growing body of literature highlighting the importance of antipoverty policies for reducing firearm suicide.