[en] This study emanates from the work in Oskarshamn to build a process for public participation related to the site selection for a nuclear waste repository (the 'Oskarshamn model'). The idea was to see how these experiences could be useful in a broader context of decision making in complex issues, especially considering issues of common interest in the Baltic Sea Region. A pre-study for a 'Decision Institute', DECI, was initiated to describe problems in today's society that DECI would address, explore methods for the enhancement of transparency and public participation, and to suggest approaches for research and application. The study was financed by Swebaltcop (a EU Baltic Sea Co-operation Programme), the Regional Council in Kalmar County, and the Municipality of Oskarshamn. It was conducted by an interdisciplinary research group from Karinta-Konsult, the Royal Institute of Technology and the University of Gothenburg. Besides the work in Oskarshamn, results from the RISCOM Pilot project and current developments in Environmental Impact Assessment (EIA) and Strategic Environmental Assessment (SEA) were in particular taken into account. This presentation: - Addresses problems with decisions on complex issues. - Discusses reasons for public participation. - Gives a framework for transparency. - Describes a number procedures aimed at public participation and transparency. - Gives a framework for how procedures can be structured. - Gives some conclusions with regard to present status and future work. (author)