Unintended Detrimental Effects of the Combination of Several Safety Measures—When More Is Not Always More Effective

Abstract

To ensure safety-related behavior in risky operations, several safety measures, such as safety-related rules and safety management systems including audits, rewards, and communication, are implemented. Looking at each single measure, it is reasonable to assume that each one leads to rule compliance, but how do they interact? In an experimental study, we varied (1) the salience of either safety, productivity, or both, (2) the reward for the compliance and punishment for a violation, (3) the communication of audit results (result- or process-based), and (4) the gain and loss framing of performance indicators. In a 3 × 2 × 2 × 2 factorial between-group design, 497 engineering students in the role of Control Room Operator participated in a five hour simulation of a production year of a chemical plant. Looking at single effects, salient safety goals led to a low number of rule violations compared to the salience of production goals. Interestingly, the interaction of several measures showed that particular combinations of measures were highly detrimental to safety, although altogether, they were assumed to reduce risks. For practice, this means that the effects of safety measures depend on their particular combination and can lead to unwanted effects.