Recruitment of Low-wage Workers for a Time-sensitive Natural Experiment to Evaluate a Minimum Wage Policy: Challenges and Lessons Learned

Abstract

Natural experiments are often used for answering research questions in which randomization is implausible. Effective recruitment strategies are well documented for observational cohort studies and clinical trials, unlike recruitment methods for time-sensitive natural experiments. In this time-sensitive study of the impact of a minimum wage policy, we aimed to recruit 900 low-wage workers in Minneapolis, Minnesota, and Raleigh, North Carolina. We present our recruitment strategies, challenges, and successes for participant screening and enrollment of a difficult-to-reach population.

A Difference-in-Difference Study Evaluating the Effect of Minimum Wage Policy on Body Mass Index and Related Health Behaviors

“…While differences in the racial/ethnic composition of the sample were expected, the magnitude of gender and age differences between the two cities was unexpected. Community engagement processes and political sentiments were naturally unique at each site, and may have led to different patterns of enrollment (Shanafelt et al, 2021). Although these differences exist, they can be addressed in the study's statistical analyses; the research team collected individual-level data on these variables and will be able to adjust for these potential confounders more precisely than if group-level attributes were assigned to each individual.…”

“…Several other checks assessed whether Raleigh was an appropriate control site, including: (1) checking the parallel trends assumption for BMI over the previous 10-year period using Behavioral Risk Factor Surveillance System SMART data; (2) comparing the obesity rate, other cost of living measures, and common industries across cities; and (3) checking that the metropolitan areas demonstrated reasonably similar economic trends in relevant industries. Additional details about selection of the comparison site, including a comparison of site demographic indicators guiding the site selection, can be found elsewhere (Shanafelt et al, 2021).…”

“…These workers were considered likely to be affected by the minimum wage over its years-long implementation (Arai, 1997;Doeringer and Piore, 1975). Additional details about recruitment processes for participants can be found elsewhere (Shanafelt et al, 2021).…”

Equity at the Ballot Box: Health as a Resource for Political Participation Among Low-Income Workers in Two United States Cities

“…Although the data set was originally designed to evaluate a minimum wage ordinance and not propensity to vote, it is unique and has great value for the investigation of health and political participation, as the survey asks about many measures of health as well as voter turnout in local elections in two distinct urban contexts. Raleigh serves as the control site because it is located in a state with a minimum wage preemption law 1 but has similar relevant demographics to Minneapolis based on United states Census data (Shanafelt et al, 2020). This broad study, of which the cross-sectional survey examined here is just one component, is called the Wages Study.…”

“…This community-based sample was recruited though active recruitment at community organizations and events, as well as passive strategies, (e.g., flyers, advertisements). Wages study recruitment strategies are discussed in more detail in a previous publication (Shanafelt et al, 2020). Participants were eligible if they: 1) were 20 years old or older, 2) worked at least 20 h a week at a wage of less than $11.50/hour in Minneapolis/ Raleigh OR were employed at that wage within the last 6 months and were currently seeking work in Minneapolis/Raleigh, 3) planned to serve in the workforce for at least 5 years, 4) had a means of being contacted for follow-up, and 5) spoke English or Spanish.…”