Common Data Element (CDE)
Common Data Element (CDE) are standardized key terms or concepts, established so that they may be used in clinical research or in studies, to enhance data quality and so that the data can be used across sites and over time. The common data element is similar to an attribute; it functions as a key, which can then map to an associated value. Development and use of CDEs supports standardization of terms and facilitates data sharing so that data can be compared and combined across studies; research findings can then be generalized with respect to different research institutions, diverse populations, different regions, and interventions. 
NIH definition of CDE: A data element that is common to multiple data sets across different studies.
Common data elements have been developed as a response to the healthcare industry’s need to develop clinical data content standards that can be used both for patient care in clinical settings as well as for secondary data uses. These may include disease surveillance, population and public health, quality improvement, clinical research, and reimbursement. The National Institutes of Health as well as other groups and institutions advocates that researchers use CDEs in research, including those derived from electronic health records.
Use of CDEs can reduce the cost and complexity of a study, and promote collective use for studies involving small sample sizes. Use of CDEs promotes robust analysis and accelerate evaluations of a larger body of scientific literature.
CDE are stored in collections, repositories, or libraries. Several are readily available and free although registration may be required for access. Researchers can find pre-defined CDEs already developed and available in sets for use with case report forms (CRFs). The National Institutes of Health (NIH) has an extensive repository of CDE collections, and researchers are encouraged to use them in human subject research, such as clinical studies, registries, or biorepositories. CDEs are developed within many disciplines and it is recommended they be used to establish uniformity when collecting or using clinical data.
NIH has an extensive collection of CDE repositories, which can be found on their Resource portal:
General Categories: These include CDEs used across several research disciplines. Examples from NIH listings include:
- NIH Common Data Element (CDE) Resource Portal - Collections and Efforts
- PhenX Toolkit
- PROMIS - validated patient-reported outcome measures
- NIH Toolbox - Validated measures of cognitive, emotional, sensory and motor functions
Focused Categories: These are specific CDEs are those that are less common to all subjects but more specific to research subcategories. Some examples include:
- NINDS Common Data Elements for neurological disorders and stroke clinical research
- NCI - biomarker harmonization
- NEI-AREDS - harmonize data across biorepositories
- NIDA - electronic health record extracted
- NCATS - Global Rare Diseases Patient Registry
- NIH - National Institute on Drug Abuse
Other CDE Repositories:
- Health & Human Services HHS.gov Common Data Element Repository (CDER) Library
- A federal-wide, online searchable repository for grants-specific data standards, definitions, and context.
Simple examples of Common Data Elements:
- Patient age
- Marital status
- Tumor grade
- Number of alcoholic beverages consumed over past 30 days
The development process generally includes four basic steps:
- A need for a CDE or group of CDEs is identified. This may generate from an organization, an individual investigator, sponsor, or funding entity; it may initiate from a regulatory agency such as the FDA, or from a professional society or an entire research community.
- Stakeholders & expert groups are identified and meet to develop or select CDE for an identified purpose
- Iterations & updates are made, in initial development and with ongoing input from broader community
- CDEs are endorsed by the developing body or organization. Their use is then required, recommended, encouraged, or acknowledged as an option for use.
Submitted by B.Zentzis