ISO 9000 impact on product quality in a defense procurement environment

Purpose – The purpose of this paper is to provide insights into the relationship between ISO 9001 conformance of suppliers and the quality of products they provide, within a procurement system of a manufacturer operating under contracts with the US Department of Defense. Design/methodology/approach – Chi‐square tests of independence were performed to compare the receipt acceptance rate of material provided by ISO 9001‐conforming suppliers to that of non‐ISO 9001‐conforming suppliers, for more than 46,000 receipts representing 21 material commodity groups provided by almost 800 suppliers. Acceptance of receipts required conformance to both hardware and paperwork requirements. Tests were also performed on data subsets, to determine the impact of ISO 9001 conformance on product quality for each of the 21 material commodity groups, for manufacturers versus distributors, and for two material control levels. Findings – For the overall data set, and for the majority of data subsets analyzed, the product quality of non‐ISO 9001‐conforming suppliers was significantly better than that of ISO 9001‐conforming suppliers. When only hardware non‐conformances were considered to cause rejections, the results were similar, but effect sizes were generally smaller. Research limitations/implications – The quantities of receipts and suppliers included in this investigation were very large; however, care should be exercised in generalizing the results, because of the potential influence of the defense industry‐related requirements imposed upon the material and the suppliers. Originality/value – This is believed to be the first paper to investigate the impact of ISO 9001 conformance on product quality using a large quantity of actual product data, for both ISO 9001‐conforming and non‐ISO 9001‐conforming suppliers, in contrast to numerous assessments of quality impact performed using interview and survey data.