A scoping review of the evidence base for the performance of leading indicators for improving safety outcomes: Available evidence, implications for practice and future directions

Abstract

Introduction: Safety performance indicators are important to assess and prevent work-related incidents, which are associated with high global morbidity and mortality. Safety can be measured using lagging indicators (past workplace incidents) or leading indicators (proactive measures to prevent incidents). Leading indicators in occupational safety and health (OSH) are already used in several industries, though it is unclear whether their use is supported by published evidence.

Methods: We undertook a scoping review to identify studies evaluating the performance of OSH leading indicators. Literature searches (8 databases, August 2023) identified primary studies evaluating the impact of leading indicators on any safety outcomes in any industry. Researchers systematically identified and extracted relevant studies. No two studies assessed the same research question, preventing meaningful synthesis of the performance of leading indicators. Instead, we mapped the available studies to understand the quality and nature of this important evidence base.

Results: The 48 studies comprise a substantial, though disparate, evidence base. Although most reported a positive impact of leading on lagging indicators, overall the evidence base was weak: (1) study designs were not appropriate for determining causality; (2) internal validity of studies was moderate to low; (3) studies were poorly generalizable. The biggest challenge was the inability to compare findings across studies.

Conclusions: Decisions on which leading indicators to use should be based on evidence that they improve safety. Future research should take measures to improve and standardize study design and conduct. Developing an OSH-specific evidence standards framework is likely to guide and assist this process.

Practical applications: Identifying recommendations for practice was difficult due to the quality and heterogeneity of the evidence base. Future studies should improve approaches to minimizing bias and identify common tools to measure both leading and lagging indicators. To achieve this, we encourage practitioners and researchers to collaborate and share data.

Keywords: Key performance indicators; Lagging indicators; Leading indicators; Occupational safety and health; Safety outcomes; Scoping review.