An item-response theory approach to safety climate measurement: The Liberty Mutual Safety Climate Short Scales

•This study shortened the original Zohar and Luria (2005) 32-item safety climate scale which is widely used in the scientific and practical field.•Item response theory (IRT) analysis was conducted using a sample of 29,179 frontline workers from various industries.•Two lengths of shortened scales were developed in the study which had good reliability and high correlation with the original scale scores.•The shortened scales will be valuable for academic research and practical survey implementation in improving occupational safety.

Zohar and Luria's (2005) safety climate (SC) scale, measuring organization- and group- level SC each with 16 items, is widely used in research and practice. To improve the utility of the SC scale, we shortened the original full-length SC scales. Item response theory (IRT) analysis was conducted using a sample of 29,179 frontline workers from various industries. Based on graded response models, we shortened the original scales in two ways: (1) selecting items with above-average discriminating ability (i.e. offering more than 6.25% of the original total scale information), resulting in 8-item organization-level and 11-item group-level SC scales; and (2) selecting the most informative items that together retain at least 30% of original scale information, resulting in 4-item organization-level and 4-item group-level SC scales. All four shortened scales had acceptable reliability (≥0.89) and high correlations (≥0.95) with the original scale scores. The shortened scales will be valuable for academic research and practical survey implementation in improving occupational safety.