Open Journal of Medical Psychology, 2014, 3, 189-201 Published Online April 2014 in SciRes. http://www.scirp.org/journal/ojmp http://dx.doi.org/10.4236/ojmp.2014.33021 How to cite this paper: Hübner, G. and Lippke, S. (2014) Investigating and Promoting the Decision towards Signing an Or- gan Donation Card. Open Journal of Medical Psychology, 3, 189-201. http://dx.doi.org/10.4236/ojmp.2014.33021 Investigating and Promoting the Decision towards Signing an Organ Donation Card Gundula Hübner 1,2 , Sonia Lippke 3 1 Medical School Hamburg, Hamburg, Germany 2 Martin-Luther-University Halle-Wittenberg, Halle, Germany 3 Jacobs University Bremen, Bremen, Germany Email: gundula.huebner@psych.uni-halle.de , s.lippke@jacobs-university.de Received 29 December 2013; revised 29 January 2014; accepted 6 February 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Using the Health Action Process Approach (HAPA) as a theoretical backdrop, the aim of this re- search, which consists of two studies, was to understand the process of goal setting and deciding to sign an organ donor card. In Study 1 (N = 550), we tested the HAPA’s stages in terms of discontinu- ity patterns in the variables predicting goal setting for organ donation. As expected, multigroup structural equation modeling revealed discontinuity patterns in terms of different prediction pat- terns. In Study 2 (N = 389), the efficacy of a planning intervention that aimed to foster the transla- tion of goals into behavior was tested: participants who received the intervention were more like- ly to order a donor card than those who did not. Contrary to the HAPA’s predictions, within the in- tenders group the planning intervention did not stimulate behavior more frequently than in the control condition. In general, the stage-specific planning intervention is of practical importance, as it shows that brief and relatively inexpensive communication can enhance organ donation beha- vior. Keywords Planning Intervention, Stage Model, Organ Donation, Goal Setting, Self-Efficacy 1. Introduction Despite strong positive attitudes towards donating organs postmortem, and high intention to commit to such an act, only a few individuals actually sign an organ donor card. In order to promote organ donation i.e. preparatory behavior in terms of signing a donor card, it is important to understand the processes that drive this behavior. According to classical social-cognitive theories, the most immediate and important predictors of volitional, goal-