“…The procedure of modeling surgical processes by observation, especially with the objective of performance assessment in the context of surgical training (Leong et al, 2007;Megali, Signigaglia, Tonet, & Dario, 2006;Richards, Rosen, Hannaford, Pellegrini, & Sinanan, 2000;Rosen, Brown, Chang, & Hannaford, 2006) or of comparing strategies for surgical treatment (den Boer et al, 1999;Strauss et al, 2006), generally focuses on two measurement strategies: high-resolution, sensor-based measurement of the performance of a limited number of surgical actions-such as, for instance, instrument movement trajectories while placing knots-or low-resolution and simpler observer-based measurements for surgical interventions or interventional phases (e.g., Archer & Macario, 2006;Schuster, Wicha, Fiege, & Goetz, 2007), without reference to specific surgical process steps. In previous work, we proposed an approach that allows for a medium level of granularity to be used for the decomposition of surgical process steps into categories, as described in the following section, in order to accommodate the complexity and diversity of information and the high variability of surgery.…”