Key Takeaways

- Recent research uncovered severe philosophical and statistical flaws with using traditional lagging indicators as comparative measures of safety performance. The severity-based lagging indicator (SBLI) is introduced as an alternative safety metric that addresses some limitations of traditional metrics while preserving some strengths.

- SBLI is an adjusted injury rate that weights injuries by their relative severity and aggregates them into one rate. Compared to traditional lagging indicators, SBLI produces more meaningful and statistically stable trends.

- Despite its strengths, SBLI has many of the same philosophical limitations of traditional lagging indicators, such as being retrospective, prone to manipulation and based on a dated view of safety as the absence of incidents.

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The way an organization uses safety metrics to make business decisions is a direct reflection of its safety culture. Safety metrics are critical for goal setting, observing progress, benchmarking and influencing behavior (Taaffe et al., 2014). Practitioners make direct comparisons when using safety metrics to answer vital questions such as:

- “How did we perform last year compared to our peers?”

- “Did we improve as a company since last quarter?”

- “Which contractor has better safety performance?”

Ultimately, the answers to these questions drive business decisions such as resource allocation, promotion, and other forms of incentive or recognition.

Lagging indicators have been the dominant measures of safety performance for more than 50 years (Dekker & Pitzer, 2016; Lingard et al., 2017; Manjourides & Dennerlein, 2019). Among the many lagging indicators, total recordable injury rate (TRIR) is the most pervasive. Put simply, TRIR is the count of recordable injuries divided by the corresponding number of worker hours and normalized per 200,000 worker hours. TRIR persists because it is based on a single, standardized definition of a recordable injury propagated by OSHA (n.d.a). The use of a standard definition and a single method of computing a rate enables direct comparisons and simple communication. It also ensures that assessments are objective and minimally impacted by personal judgment. Although alternative measures of safety performance have emerged such as leading indicators and climate assessments, TRIR persists because it is standardized in a way that alternative metrics are not (Hinze et al., 2013; Oguz Erkal, 2022; Schwatka & Rosecrance, 2016). However, despite ubiquitous use as a comparative safety metric, recent research shows that TRIR and other traditional lagging indicators have severe statistical and philosophical limitations (Hallowell et al., 2021; Oguz Erkal et al., 2021; Toellner, 2001).

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