Using Influence Strategies to Increase the Efficacy of the NY PTO Shielding Intervention

PTO Message from previous project


Burden-U.S. farmers face myriad dangers each day and of these, machinery entanglements are among the most frequent.1 Unlike farm incidents such as tractor overturns, machinery entanglements are more likely to cause permanent disability than lead to a fatality. In a study of 700 power take-off (PTO) entanglements, 60% resulted in non-fatal injuries.2 Many of these injuries involved amputations, which can be painful, debilitating, and costly: PTO incidents are responsible for nearly 40% of all agricultural-related medical expenses.3 Between 2008 and 2014, approximately 8% of farm fatalities were due to machinery entanglements and 36% of these occurred with PTO drivelines.4 Despite efforts to increase proper PTO guarding, a safety precaution that can significantly reduce the risk of entanglements, many drivelines remain unshielded.5-8

In the preceding study (2011-2016), the research team conducted random inspections of PTO shields throughout the state. During these audits, 1,470 implements on 211 farms were inspected: only 56.7% of PTO drivelines were found to be properly shielded. The team also worked to identify barriers and motivators to PTO shielding through qualitative studies. This information was used to identify an improved PTO shield (which eliminated or reduced many of the barriers identified by farmers) and develop a targeted social marketing campaign to encourage shielding, which was promoted throughout a six-county intervention region. Though developed in conjunction with farmers, the social marketing campaign had a limited effect. In the counties exposed to the social marketing campaign, a purchase rate of just 14 shields per 10,000 farms was observed (compared to an estimated 31 shields per 10,000 farms in the control counties).

The research conducted on driveline shielding behaviors in NY indicates that previous history with shields and social norms are likely to be strong determinants of user behavior. In order to increase interest in PTO shields, we propose to conduct a randomized, controlled trial of six different 'Principles of Influence' (or hereby referred to as 'influence strategies') that will serve as a booster to enhance the impact of the existing statewide PTO social-marketing intervention. These six influence strategies include: reciprocity, consistency, consensus, liking, authority and scarcity. By trialing a different influence strategy in each of six different agricultural communities in NY, it will be possible to identify the influence approaches that will most effectively increase PTO shield installation or shield replacement on NY farms. This information may also be applied to the adoption of other safety behaviors or technologies.

The long-term goal of the proposed study is to gain a better understanding of how agricultural workers and business owners may be persuaded to adopt best practices that they have been previously resistant to put into practice. Based on previous research conducted in the farm community, farmers are aware of entanglement dangers, but lack the appropriate motivation to replace missing or broken shields. The objective of this application is to build on previous research and intervention development efforts conducted by the research team, in order to facilitate a 20% increase in NY PTO shield sales between 2016 and 2021.

Need-Research conducted by the research team on PTO shielding behaviors indicates farmers' prior history with complicated, expensive driveline-shielding has impeded adoption. Although many barriers have been removed as a result of prior intervention activities (i.e. cost-reduction, increased ease-of- driveline maintenance and the development of universal shield models), it is clear that farmers require additional persuasion to try new and improved PTO shield designs. To explore this gap in progress, we seek to:


Specific Aim #1: Implement an influence strategy in six distinct agricultural communities to serve as a booster to an existing, statewide PTO shielding social marketing campaign.

Specific Aim #2: Evaluate the impact of these influence strategies by measuring changes in opinion (as outlined in Kelman's 'Processes of Opinion Change')9 and changes in PTO sales.

Specific Aim #3: Enhance the impact of an existing, statewide PTO social marketing campaign.

NORA priorities10 addressed

Strategic Goals 3 (Outreach, communications, and partnerships)), and 4 (Agricultural Safety)


Research Team

Julie Sorensen, PhD

Paul Jenkins, PhD                 

Pam Tinc, MPH