Table 1: CDS Implementation Needs, Standards that Can Facilitate Implementation, and Gaps and Challenges

CDS Implementation Need and Related Standard Needs	Specific Standard Need	Current and Emerging Standards	Gaps and Challenges
CDS implementation need: need to communicate with other systems about relevant health care concepts Related standard needs: standards for data representation and mapping	Standard terminologies	Unified Medical Language System [36] and component terminologies (e.g., SNOMED SNOMED [20], LOINC [37], RxNorm [38])	Overlapping and semantically non-compatible terminologies are in concurrent use, including non-standard terminologies
	Standard information models	HL7 version 2 and version 3 information models [39] openEHR archetypes [40] ASTM International Continuity of Care Record [41] HL7-ASTM International Continuity of Care Document [42] HL7 virtual medical record (vMR) standard (under development) [43]	Insufficiently tight binding to terminologies Too much flexibility and complexity in models designed for expressive documentation rather than for CDS Hard to implement/understand Lack of tooling Lack of standard information models on inputs and outputs for CDS Low adoption
	Standards for patient data expected to be available for CDS	HL7 virtual medical record (vMR) standard (under development) [43]	Different granularity and scope of data being collected
	Standard approaches for terminology and ontology inferencing	HL7 Common Terminology Services standard [46]	Many terminologies are semantically incompatible
CDS implementation need: need to create and represent clinical knowledge that can be used for CDS Related standard needs: standards for knowledge representation	Standardized representation of clinical knowledge in non-executable format suitable for translation into executable format	ASTM International Guideline Elements Model (GEM) standard [27]	Significant medical knowledge exists outside of individual clinical practice guidelines and across multiple guidelines Most knowledge continues to be produced in non-standardized formats No clear path from non-executable to executable knowledge
	Standardized representation of clinical knowledge in an executable format	Standards for representing clinical rules (HL7 Arden Syntax standard [8], HL7 GELLO standard [9]) Standards for representing knowledge documents (HL7 Structured Product Label [51] standard, HL7 Order Set draft standard [52], HL7 Health Quality Measures Format draft standard [53])	No widely agreed upon standard for representing clinical practice guidelines Limited tooling and support for implementation Minimal availability of compliant knowledge in most cases
CDS implementation need: need to utilize clinical knowledge to deliver CDS interventions within health information systems Related standard needs: standards for leveraging knowledge resources to deliver CDS	Standardized approaches to utilizing machine-executable clinical knowledge to generate CDS	Standards for accessing CDS capabilities through a service call (HL7 Decision Support Service draft standard [33], OMG Decision Support Service standard [34], HL7 Context-Aware Knowledge Retrieval (“Infobutton”) standard [56])	Semantics of service payloads still undergoing standardization (e.g., through vMR project) No standard for identifying and retrieving machine-executable medical knowledge resources themselves No commonly accepted meta-data model for knowledge resources
	Standardized approaches to interacting with health information systems to deliver CDS	Standards for retrieving patient data from health information systems (HL7 Retrieve, Locate, and Update Service draft standard [58]; various information model and terminology standards) Standards for EHR functionality (HL7 EHR Functional Model [59], Certification Commission for Health Information Technology certification criteria [60])	Standards for EHR functionality are not defined in a semantically interoperable manner Lack of standards on EHR services (e.g., for order placement, alert delivery) Current HL7 vMR project is still in development and does not encompass EHR services Lack of use of standard business process modeling approaches in health care Need to accommodate care settings with varying degrees of health information system infrastructure (or none at all)