Organizations and researchers often encounter difficulties when evaluating organizational-level stress management interventions. When interventions fail, often it is unclear whether the intervention itself was ineffective, or whether problems with implementation processes were to blame. In this paper we describe the development of questionnaire items that allow employees to report on their appraisals of aspects of intervention process issues that are frequently thought to be related to intervention outcomes. The study was carried out as part of the evaluation of a teamworking intervention implemented in the elderly care sector in Denmark. Using a combination of information gathered from published intervention research and qualitative data collected from participants involved in an intervention, questionnaire items were developed and their sensitivity, reliability, and validity were tested. Confirmatory factor analysis revealed five independent factors: line manager attitudes and actions, exposure to components of the intended intervention, employee involvement, employee readiness, and intervention history. They all showed significant correlations with post-intervention outcomes (job satisfaction, well-being, and self-efficacy). Line manager attitudes and actions showed particularly strong and unique relationships with outcome measures. We refer to this new group of scales for evaluating employees’ appraisals of an intervention as the Intervention Process Measure (IPM). Our findings indicate that such a measure has the potential to improve the evaluation of interventions.