1. Institute for Design & Assessment of Technology, Argentinierstrasse 8/187, Vienna University of Technology, A-1040 Vienna, Austria. Tel.: ; Fax: ; E-mail: mrauhala@pop.tuwien.ac.at.
2. National Research and Development Centre for Welfare and Health, STAKES, P.O. Box 220, FIN-00531 Helsinki, Finland. Tel.: ; Fax: ; E-mail: paivi.topo@stakes.fi