OBJECTIVES: Prevention Index (PI-TOP) is a practical measurement tool which is currently used to monitor injury prevention activities at workplaces. This 12-item scoring system has 3 subscales rating technical, organisational and personnel-related internal safety conditions of a company. The reliability and validity of this instrument were evaluated in a cross-sectional survey in the German metal industry during the time between December 2011 and May 2012.
METHOD: The inter-rater-reliability of this instrument was examined by 2 trained supervisors of the German Social Accident Insurance Institution for the Woodworking and Metalworking Industries in 128 companies. The agreement of the double ratings was quantified by interclass correlation coefficient (ICC) and absolute agreement of the rating values.Construct validity of the score was examined by principle component factor analysis while content validity was evaluated by quantifying the association between PITOP-values and 5-years injury rates of 35 000 companies. Poisson regression analysis was performed to assess the strength of the association adjusted for company size and related industrial sectors.
RESULTS: Our analysis indicate a moderate to good inter-rater-reliability (ICC=0.46-0.75) of PITOP-values with an absolute agreement between 72% and 81%. Factor analysis identified three component subscales which meet exactly the structural measure theory behind the score. The Poisson regression analysis demonstrates that PITOP-values ≥7 in the T-, O- and P-subscales are associated with a decrease of injury rates.
CONCLUSIONS: Because this analysis indicates that PITOP is a valid and reliable instrument, it will be used to monitor safety conditions at workplaces in a longitudinal practical approach.