The goal of this project was to evaluate approaches of determining the numerical value of a safety inspection score that would activate a reward in an employee safety incentive program. Safety inspections are a reflection of the physical working conditions at a construction site and provide a safety score that can be used in incentive programs to reward workers. Yet it is unclear what level of safety should be used when implementing this kind of program. This study explored five ways of grouping safety inspection data collected during 19 months at Harvard University-owned construction projects. Each approach grouped the data by one of the following: owner, general contractor, project, trade, or subcontractor. The median value for each grouping provided the threshold score. These five approaches were then applied to data from a completed project in order to calculate the frequency and distribution of rewards in a monthly safety incentive program. The application of each approach was evaluated qualitatively for consistency, competitiveness, attainability, and fairness. The owner-specific approach resulted in a threshold score of 96.3% and met all of the qualitative evaluation goals. It had the most competitive reward distribution (only 1/3 of the project duration) yet it was also attainable. By treating all workers equally and maintaining the same value throughout the project duration, this approach was fair and consistent. The owner-based approach for threshold determination can be used by owners or general contractors when creating leading indicator incentives programs and by researchers in future studies on incentive program effectiveness.
Keywords: Leading indicators; construction; incentives; reward threshold; worksite safety program.