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Comparative effectiveness of training alternatives for the EPA’s Worker Protection Standard regulation among immigrant Latino farmworkers (Grzywacz et al., 2022)

Review Guidelines

Absence of conflict of interest.

Citation

Grzywacz, J. G., Gonzales-Backen, M., Liebman, A., Trejo, M., Ordaz Gudino, C., Trejo, M., Economos, J., Xiuhtecutli, N., & Tovar-Aguilar, J. A. (2022). Comparative effectiveness of training alternatives for the EPA’s Worker Protection Standard regulation among immigrant Latino farmworkers. Journal of Occupational and Environmental Medicine, 64(2), 140-145.

Highlights

  • The study's objective was to examine the impact of the Worker Protection Standard (WPS) Entrenamiento de Pesticidas e Insolación que es Culturalmente Apropiada (PISCA) training on pesticide safety knowledge and behavior among immigrant Latino farmworkers. PISCA is an EPA-approved WPS training that is culturally and linguistically tailored for a Latino audience and is led by a facilitator.  
  • The study was a three-arm randomized controlled trial that used survey data to compare outcomes of study participants who were randomly assigned to receive the WPS PISCA training to outcomes for participants in a comparison group. Individuals in the comparison group either received an alternative EPA-approved WPS training that is video-based and not tailored to Latino farmworkers, or an in-person training on heat stress that is contextually and linguistically tailored for Latino farmworkers.   
  • The study found that WPS PISCA training participants had significantly greater retention of pesticide safety knowledge and greater change in pesticide safety behaviors, compared to participants in the comparison group. 
  • The quality of causal evidence presented in this report is moderate because it was a randomized controlled trial with high attrition, but the authors ensured that the groups being compared were similar before the intervention. This means we are somewhat confident that the estimated effects are attributable to the WPS PISCA training, but other factors might also have contributed.

Intervention Examined

Worker Protection Standard (WPS) Entrenamiento de Pesticidas e Insolación que es Culturalmente Apropiada (PISCA) training

Features of the Intervention

The revised Worker Protection Standard (WPS) is a federal regulation that protects farmworkers from pesticide poisoning. The regulations have been in effect since 2017 and are overseen by the Environmental Protection Agency (EPA). These trainings are free, and per the updated WPS are mandatory once a year.  

This study focused on the impact of the EPA-approved WPS PISCA training, which is culturally and contextually tailored for Latino farmworkers and is facilitator-led. The comparison intervention was either an EPA-approved WPS training that is delivered by video and is not tailored to Latino farmworkers, or a culturally and contextually tailored heat-illness curriculum that is facilitator-led.

Features of the Study

The study was a three-arm randomized controlled trial that compared outcomes for participants who received the WPS PISCA training (the focal intervention), an alternative video-based WPS training, and a placebo heat stress training. The study recruited participants from farmworker communities in Florida and Georgia. Recruitment strategies varied over time and by population type. To engage H-2A workers, Community Advisors engaged with owners and crew leaders at large farm establishments to offer the free mandatory WPS training. To engage non H-2A workers, Community Advisors identified neighborhoods and enclaves where significant numbers of farmworkers resided, visited these areas to share information about the training, and followed up individually with interested individuals. At the beginning of each safety event, participants who self-identified as Latino and reported recent agricultural work were invited to participate in the study. Advisors and interested participants were unaware of the specific curricula featured at each event. 

The study included 339 Latino farmworkers living in Florida or Georgia. Participants were mostly men and the average age was 29. All but two participants were born outside the US, primarily in Mexico. Most participants had an H-2A visa. 

A total of 136 participants were randomly assigned to receive the WPS PISCA training. The comparison group included 121 participants randomly assigned to receive the WPS video training and 82 individuals assigned to receive the heat-illness training.   

The authors collected data through interviewer-assisted self-reported surveys. Surveys were conducted before the training, immediately after the training, and 3 months after the training. The authors used statistical models to compare the outcomes between the PISCA intervention group and the comparison group while controlling for age, gender, H-2A visa status, worker type (migrant or seasonal worker), and years of farm work experience.

Findings

Health and Safety 

  • The study found that participants assigned to the WPS PISCA training had significantly higher retention of pesticide safety knowledge at the 3-month follow-up, compared to participants in both the full comparison group (those receiving the alternative video-based WPS training or the placebo heat stress illness training) and compared to the subgroup of participants receiving the alternative WPS training.  
  • The study found that participants assigned to the WPS PISCA training reported significantly greater pesticide safety behaviors at the 3-month follow-up, compared to participants in both the full comparison group and the subgroup receiving the alternative WPS training.

Considerations for Interpreting the Findings

The study is a randomized controlled trial with high attrition. Therefore, the study is not eligible for a high causal evidence rating, the highest rating available for experimental designs. However, the authors ensured that the groups being compared were similar before the intervention.  

The study authors estimated multiple impacts on outcomes related to health and safety. Performing multiple statistical tests on related outcomes makes it more likely that some impacts will be found statistically significant purely by chance and not because they reflect program effectiveness. The authors did not perform statistical adjustments to account for the multiple tests, so the number of statistically significant findings in this domain may be overstated.

Causal Evidence Rating

The quality of causal evidence presented in this report is moderate because it was a randomized controlled trial with high attrition, but the authors ensured that the groups being compared were similar before the intervention.  This means we are somewhat confident that the estimated effects are attributable to the WPS PISCA training, and not to other factors.

Reviewed by CLEAR

December 2024