Absence of conflict of interest.
Citation
Highlights
- The study's objective was to examine the impact of minimum wage increases on health outcomes.
- The study used a difference-in-differences design to compare changes in outcomes before and after the implementation of the minimum wage increases. The author used panel survey and state minimum wage data and statistical models to compare differences between intervention and comparison group members.
- The study found that non-Hispanic White men in the intervention group had a significantly lower risk of obesity, while non-Hispanic White women in the intervention group had a significantly a higher risk. These women also had a significantly lower risk of moderate psychological distress. Women of color in the intervention group had a significantly higher risk of fair or poor health status.
- This study receives a moderate evidence rating. This means we are somewhat confident that the estimated effects are attributable to minimum wage increases, but other factors might also have contributed.
Features of the Study
This study examined the impact of state minimum wage increases on health outcomes, including obesity, hypertension, fair or poor self-reported health, and moderate psychological distress. The author used a difference-in-differences design to compare health outcomes between the intervention group and comparison group, before and after implementation of the minimum wage increases. The study sample was selected from a national dataset, the 1999-2017 Panel Study of Income Dynamics (PSID). Eligible participants had to be between 25 and 64 years old, be heads of households or their partners/spouses, and either be employed or unemployed while actively seeking work for at least half of the time. Working-age adults with a high school education or less, designated as “likely affected” by the minimum wage increases, were included in the intervention group. In contrast, working-age adults with some college education or higher, designated as “likely unaffected” by the minimum wage increases, were included in the comparison group. The sample included 13,730 working-age adults from various states in the U.S., with 6,166 in the intervention group and 7,564 in the comparison group. Among the participants, 49.9% were female, 44.1% identified as people of color, and the average age was 34.7 years.
The primary data sources were the demographic and self-reported health outcome data from the 1999-2017 PSID and the 1999-2017 state minimum wage data from the University of Kentucky Center for Poverty Research's (UKCPR) National Welfare Data, sourced from the Bureau of Labor Statistics' Wage and Hours Division. The author examined a $1 minimum wage increase from the same year as the outcome (current minimum wage) and from two years prior (two-year lagged minimum wage). Since wage changes can happen anytime in the year, the two-year lagged minimum wage ensured the wage rate was determined at least 13 months before assessing results. It also allowed for the study of health effects that may take longer to appear. The author used a statistical model to assess the differences in outcomes between the intervention and comparison groups, before and after implementation of the minimum wage increases.
Findings
Health and safety
- For the overall sample, the study did not find any significant differences in health outcomes between the intervention and comparison groups, for the current and two-year lagged minimum wage.
- The study found that for the two-year lagged minimum wage, non-Hispanic White men in the intervention group had a significantly lower risk of obesity relative to the comparison group. In contrast, non-Hispanic White women in the intervention group had a had significantly higher risk of obesity.
- The study also found that non-Hispanic White women in the intervention group had significantly lower risk of moderate psychological distress relative to the comparison group, for the current and two-year lagged minimum wage.
- The study found that women of color in the intervention group had significantly higher risk of fair or poor health status relative to the comparison group, for the current minimum wage.
Considerations for Interpreting the Findings
The author used education levels to determine who might be impacted by minimum wage increases to create the study groups. This could create bias since women and people of color often earn lower wages even with higher education compared to White men. Additionally, some workers with a high school diploma or less might earn more than the minimum wage, which presents an issue for using education to create the groups for comparison. Also, the author combined certain racial and ethnic groups with smaller numbers in the dataset into a single subgroup for people of color, limiting understanding of the findings for specific races and ethnicities. Lastly, the study does not account for individuals who might commute to work across state lines. Changes in minimum wage laws in one state could impact the health of those in a neighboring state that does not have such laws, potentially affecting the interpretation of the findings.
Causal Evidence Rating
The quality of causal evidence presented in this report is moderate because it was based on a well-implemented nonexperimental design. This means we are somewhat confident that the estimated effects are attributable to the minimum wage increases, but other factors might also have contributed.