Relationship between Construction Safety and Quality Performance

It is well established that the project cost, quality, safety, and duration are the four critical elements that contribute to project success. Past literature has established theoretical relationships between construction safety and quality on the basis of opinions of industry experts. This is the first empirical inquiry into the relationship between safety and quality, testing the null hypothesis that there is no statistical relationship among quality performance indicators and safety performance indicators. To test this hypothesis, empirical data were collected from 32 building construction projects, ranging in scope from $50,000 to $300 million dollars. Several quality metrics (e.g., cost of rework per $1M project scope and rate of rework per 200,000 worker-hours) were used as predictor variables and first aid and Occupational Safety and Health Administration (OSHA) recordable injury rates were used as response variables. Linear regressions among the predictor and response variables showed that there are two statistically significant relationships: the OSHA recordable injury rate is positively correlated to rework ($r^2=0.968$; $p\text{-}\mathrm{value}=0.032$) and the first aid rate is positively correlated to number of defects ($r^2=0.548$; $p\text{-}\mathrm{value}=0.009$). To understand why these relationships exist and to identify specific strategies that promote both safety and quality, open-ended interviews were conducted with project managers. These individuals indicated that the most compelling reason for the strong positive correlation between rework and injuries is the fact that rework involves demolition, schedule pressure, and unstable work processes. They also noted that devoting resources to preplanning, allowing the necessary time to complete tasks correctly the first time, encouraging leadership at the workface, and encouraging workers to take pride in their work are all strategies that promote both safety and quality.