On Effect Assessment in Work Environment Interventions – A Literature Overview and Methodological Reflection

Despite many positive case studies our overview of the work environment intervention (WEI) research literature finds mixed results. There is support for the profitability of WEI investments such as training and personnel policies at the organisational level but less clear results for disorder reductions. The financial benefits of WEIs were greater for performance gains than for reduced sickness costs. Multifactor interventions are widely seen as key to successful intervention but are difficult to evaluate and unused in experimental studies. Review inclusion criteria excluding studies with good interventions but non-experimental evaluations, pose a quality criteria selection bias. Difficulties in proving WEI effectiveness may depend on views of what constitutes good scientific quality. WEI effects are clear in some cases but are difficult to show in others. Evaluation poses methodological challenges that contribute to the lack of clear evidence for WEI effectiveness. There is a need for more practical multifactor WEIs and non-experimental evaluation strategies suited to today’s complex systems. RELEVANCE: Ergonomists and managers should understand that the problems in 'proving' the effectiveness of ergonomics are related to perceptions of what constitutes proof. Progress in the practise of ergonomics should recognise the difficulty of organisational change, the weaknesses of experimental traditions, and the need for multifactor interventions that reach deep into the work process to maximise impact. Isolating effects is difficult but this does not mean no effects exist.