Intuitiveness, attractiveness and efficiency are in general important characteristics of high quality User Interfaces (UI). In the case of a Mass Casualty Incident (MCI) and other life threatening situations good user interfaces are essential as every second counts in these time-critical situations. Finding the best way to interact with the system is a challenge with many open issues. Therefore, it is essential to test different UI alternatives to determine important usability issues as those mentioned before. This paper focuses on the research question how patients can be selected on a map application which runs on a rugged tablet PC. A rugged tablet PC is in general heavy because of its robustness, which introduces a new special requirement in addition to the existing UI requirements. Consequently, since the users are forced to hold the tablet PC with two hands because of its heaviness, they have to perform all UI interaction with the thumbs. This implies that the users are not able to reach every item on the screen of the tablet PC. Therefore all UI elements have to be either on the left or on the right hand-side of the screen. The implementation and the evaluation of the UI alternatives presented in this paper were performed within the scope of the !SpeedUp projectootnoteThe project !SpeedUp is funded by the German Federal Ministry of Education and Research (BMBF) within the programme "Research for Civil Security" (May 1st, 2009 - April 30th, 2012, FKZ: 13N10175). Website: http://www.speedup-projekt.de.     «

Intuitiveness, attractiveness and efficiency are in general important characteristics of high quality User Interfaces (UI). In the case of a Mass Casualty Incident (MCI) and other life threatening situations good user interfaces are essential as every second counts in these time-critical situations. Finding the best way to interact with the system is a challenge with many open issues. Therefore, it is essential to test different UI alternatives to determine important usability issues as those me...     »