Background: Implementation fidelity refers to the degree to which an intervention or programme is delivered as intended. Only by understanding and measuring whether an intervention has been implemented with fidelity can researchers and practitioners gain a better understanding of how and why an intervention works, and the extent to which outcomes can be improved.

Subjective measures of company performance are widely used in research and typically are interpreted as equivalent to objective measures. Yet, the assumption of equivalence is open to challenge. We compared the use of both types of measure in 3 separate samples. Findings were consistent in showing that: (a) subjective and objective measures of company performance were positively associated (convergent validity); (b) those relationships were stronger than those between measures of differing aspects of performance using the same method (discriminant validity); and (c) the relationships of subjective and objective company performance measures with a range of independent variables were equivalent (construct validity).

It is often assumed that research over the last decade has established an effect of human resource management (HRM) practices on organizational performance. Our critical assessment of existing studies finds that, although collectively they have opened up a promising line of inquiry, their methodological limitations make such a conclusion premature. We argue that future progress depends on using stronger research methods and design that, in turn, will require large-scale long-term research at a level of magnitude that probably can only be achieved through partnerships between research, practitioner and government communities. We conclude that progress so far justifies investment in such big science. K E Y WO R D Scompany performance high performance work organization high performance work systems human resource management organizational performance Picture the scene. A leading scholar specializing in human resource management (HRM) is called to court as an expert witness by an international company that has brought a case against a firm of consultants. The company has paid several hundred thousand pounds in consultancy fees, and invested many times that amount in its personnel function, to introduce the 'performance-enhancing' HRM practices recommended by the consultants. Three years on there is no evident return on their investment. The company is suing 4 2 9 Human Relations

This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThe relationship between organizational performance and two dimensions of the widely known 'high performance work system' -enriched job design and high involvement management (HIM) -is assumed to be mediated by worker well-being.We outline the basis for three models: mutual-gains in which employee involvement increases well-being and this mediates its positive relationship with performance;conflicting outcomes which associates involvement with increased stress for workers that accounts for its positive performance effects; and counteracting effects which associates involvement with increased stress and dissatisfaction, and reduces its positive performance effects. These are tested using the UK's Workplace Finally, HIM is negatively related to job-related anxiety-comfort but this plays no mediating role in the link to performance. It is also unrelated to enriched job design. Keywords High involvement management Enriched job design Well-being Stress Job satisfaction Financial performance Labour Productivity Quality AbsenteeismMulti-level analysis 3Enriched job design, high involvement management and organizational performance:The mediating roles of job satisfaction and well-being Direct employee participation is one of the most widely advocated interventions for influencing organizational performance and worker well-being (Humphrey et al., 2007;Parker et al., 2001). It is central to modern organizational concepts such as Lawler's (1986) high involvement management (HIM), human resource management (HRM) (Guest, 1987), the mutual gains enterprise (Kochan and Osterman, 1994), and the high performance work system (Appelbaum et al., 2000;Benson and Lawler, 2003;Cappelli and Neumark, 2001).Two types of opportunity for direct participation are associated with these management models: a) the design of jobs that give their holders discretion, variety and high levels of responsibility; and b) organizational involvement methods that extend beyond the narrow confines of the job, such as teamworking, idea-capturing schemes and functional flexibility.Type a) is associated with the job redesign movement and the concept of job enrichment.Type b) is associated with the high involvement or commitment model that emerged out of this movement, particularly through its popularization by Lawler (1986) and Walton (1985).It is widely expected that these forms of employee involvement enhance the quality of individuals' working lives and their well-being and performance, and consequently the performance of organizations.Originating in the 1990s, following the emergence of high-involvement or highcommitment management, much of the research on workplace employment systems or HRM has concentrated on the performance effects of organization-level practices (e.g. Batt, 2002;Cappelli and Neumark, 2001;Huselid, 1995;MacDuffie, 1995;Wood and De Menezes, 2008). Involvement at the job level has, howe...