In an effort to characterize clinical rules, Wright et al. used four functional categories: triggers, input data, interventions and offered choices. Triggers were identified as one of the key functional dimensions of CDSS and are the start of each clinical rule. Wright and colleagues reviewed and analyzed their own extensive rule repository, using these four functional dimensions to identify and quantify the use of different taxonomic groups. They identified nine different triggers. However, by far the trigger most often used is the ‘order entered’ trigger, accounting for 94% of all the studied clinical rules and 38% of all clinical rule types. Combined with the knowledge that a patient’s drug list is also the most used ‘input data element’ in all of the studied rules, medication orders (MOs) and drug lists seem to play a key role in CDSS currently used [36, 37].