Rationale: Recently, the health-assets-concept of health promotion has been introduced by WHO. In this concept a health-asset is any factor that enhances the ability of individuals, communities, populations and/or social systems to maintain health and well-being. Aim of this concept is to identify and mobilize available resources for health promotion which exist in the target population and their setting. In addition, the investment for health model is suggested requiring a participatory approach of cooperate programme development by including project partners, representatives of the target group, stakeholders from evaluated politics and scientists. The WHO approach is expected, particularly, to reduce socioeconomic inequalities in health. Objectives: The objective of this paper is to contribute to the clarification when costs of health-asset-assessment and participatory project development should be included in programme costing. In addition, some empirical data from an ongoing study evaluating a health promotion intervention aiming at increasing physical activity of socially disadvantaged women are presented in order to illustrate that the resulting differences in programme costs may be substantial. Methodology: Essentially, it will be argued that whether or not costs of health-assets-assessment and participatory project development should be included in programme costing by programme evaluation. Roughly, three types of decisions should be distinguished: (1) the same programme should be performed in other similar settings, (2) in other similar settings programmes aiming at the same programme objectives should be developed, and (3) in other places or settings the full health-assets approach should be applied in order to develop new health promotion programmes for the targeted population. A straightforward implication for costing is a careful splitting into the project-phases of asset-assessment, programme-design, andprogramme-implementation, thus taking into account the specific requirements of the health-asset concept and the participatory approach. Different components of costs are to be considered in each phase:asset-assessment (personnel and non-personnel costs of assessing activities, e.g. interviews with members of the target group, identification of the assets); programme-design (personnel and non-personnel costs of developmental activities of all persons and groups involved, e.g. costs of needs assessment, time costs of workshops and meetings, travelling costs) and programme-implementation (personnel and non-personnel costs of recruiting participants, e.g., costs of posters, flyers and other marketing activities; and finally costs of the programme itself, e.g. rent for the gym, trainer, childcare, sports material). Results: Dependent on the scope of costing, total programme costs varied substantially. The costs of programme-implementation amounted to 44,700. Adding the costs for developing the programme-design coming to 47,300 results in total costs of 92,000; adding on top of that the costs of asset-assessment running to 35,600 would total up to 127,600. In consequence, the incremental cost-effectiveness-ratio of the programme will be rather sensitive with regard to a variation of the scope of costing. Conclusion: Depending on whether or not costs of asset-assessment and costs of programme design development are included in programme costing, total costs and hence the ICER of a preventive intervention could differ considerably. Therefore, the identification of the decision context is of crucial importance for the validity of an economic programme evaluation
