This study assesses the combined impact of multiple certifications (i.e. ISO 9001, ISO 14001, OHSAS 18001) on perceived performance dimensions related to quality, environmental and occupational health and safety. Using survey data collected from 59 Irish manufacturing plants in 2014, we employed MANCOVA and regression analysis to test our proposed hypothesis. The results suggest that companies that are simultaneously ISO 9001, ISO 14001 and OHSAS 18001 certified are significantly better performers with regard to environmental and occupational health and safety compared to companies without multiple certifications. However, from a perceived quality performance perspective, having these multiple certifications doesn’t seem to be an effective performance improvement tool.
Wiengarten, F., Humphreys, P., Onofrei, G., & Fynes, B. (2016). The adoption of multiple certification standards: Perceived performance implications of quality, environmental and health & safety certifications. Production Planning & Control, 28(2), 131-141. https://doi.org/10.1080/09537287.2016.1239847