The first data col- lection took place during a 5 months period, during which paper-based medication ordering was continued to be used (July–November 2005). The second 5-month period of data col- lection started 8 weeks after finishing the implementation process, in order to make sure that all initial problems were solved. Post-intervention data collection started in the dif- ferent wards between September 2006 and May 2008. Data were prospectively collected for 592 patients admitted dur- ing twenty weeks before and for 603 patients admitted during twenty weeks after introduction of CPOE/CDSS. In total (pre and post intervention), 4 patients did not provide consent, and thus were not included in the study. No patients or healthcare professionals opted out during the study.