Most work on high-performance work systems has examined only the direct relationship between a set of management practices and performance outcomes. This presumes that any connection operates through the incentive and motivational effects captured as ‘high-commitment’ or ‘high-involvement’ employee outcomes. No attempt has been made to examine the alternative, Labour Process conceptualization, which expects performance gains from new management practices to arise instead from work intensification, offloading of taskcontrols, and increased job strain. Using data from WERS98, we tested models based on high-performance work systems and labour process approaches. Both were found wanting, and we consider the possible implications of these failures.