Abstract: A clinical decision support system comprises a memory device having a plurality of routines stored therein, a processor configured to execute the plurality of routines stored in the memory device, the plurality of routines comprising a routine configured to receive primary clinical information from a user associated with a patient, a routine configured to derive expanded clinical information from the user-provided primary clinical information, a routine configured to identify relevant rules from a data store based on the user-provided clinical information and the expanded clinical information, a routine configured to compute a diagnostic relevancy score for each of the identified relevant rules; a routine configured to assign by the processing device the computed diagnostic relevancy score to each identified relevant rule, and a routine configured to display each identified rule in ranked order based on the rule's assigned diagnostic relevancy score.