UC Davis researchers can acquire patient data for research from the electronic medical record (EMR). The source and type of data needed dictate the process to access the data. It is necessary to understand the types of data available, sources of data, and process to gain access to data.

After required training, researchers may request access to two self-service tools (Cohort Discovery and Data Explorer) to conduct queries based on database fields in a repository of de-identified patient data. The output from both of these tools is a numeric count of patients that match the criteria identified in the query, sorted by site (as appropriate). The numeric counts can be used to assess the feasibility of a study or hypotheses by identifying whether there are sufficient prospective subjects based upon the criteria input during the query process. Researchers subsequently requiring identified data from the EMR must gain the regulatory approval required for the database that best serves their needs, as described below, AND the assistance of CTSC Biomedical Informatics through a Service Request.

Cohort Discovery

Cohort Discovery is an informatics tool that enables researchers to query a repository of patient information from UC Davis Health patients gathered from multiple sources, including electronic medical records, lab results, and demographic data. UC Davis researchers who complete an introductory training session will receive a Login ID and password for Cohort Discovery. To register for a Cohort Discovery training session, complete the online Registration Form. If you have questions or need assistance with Cohort Discovery, send an email to hs-cohortdiscovery@ucdavis.edu.

Data Explorer

Data Explorer (also known as University of California Research eXchange, or UC ReX) is a secure, web-based system that enables UC investigators to identify potential research study cohorts from 12 million de-identified patient records at the five UC medical centers. The dataset extracted will indicate the number of patients who meet the established criteria at each campus. UC Davis Researchers who complete an introductory training session will receive a Login ID and password for Data Explorer. To register for a Data Explorer Training Session, please fill out the Registration Form. Note that the training is done in conjunction with Cohort Discovery training. If you have questions or need assistance with Data Explorer, send an email to hs-ucrexdex@ucdavis.edu.

Data Request Process

De-identified data contains no PHI or HIPAA identifiers and be used for hypothesis testing and sample size determination. Researchers can access de-identified data through self-service use of UC Davis Cohort Discovery (UC Davis Health EMR data) or Data Explorer (UC Health aggregated EMR data).

Figure 1. How to access de-identified data from the UC Davis EMR.


Identified data contains one or more HIPAA/PHI identifiers and requires regulatory approval to access it. The following elements are required to access identified data from UC medical records:

  1. Regulatory approval is required for access to all identified datasets.
    1. To develop or refine a research question before you have a protocol requires Preparatory to Research Application approval by the UC Davis Health Compliance Office. Data accessed for this purpose may NOT be used for study recruitment or for publication. The investigator serves as an “honest broker” for the data accessed (see Figure 2), OR
    2. Detailed data review or a cohort for prospective recruitment once you have a protocol requires UC Davis IRB (UC Davis Health EMR data) or UC IRB Reliance (UC Health EMR data) approval. The CTSC Informatics team serves as the “honest broker” for the data delivered (see Figure 3).
  2. Assistance from the CTSC Biomedical Informatics staff is required for access to all identified datasets.

Figure 2. How to access identified data from the UC Davis EMR without a protocol.

Figure 3. How to access identified data from the UC Davis Health or UC Health EMR with a protocol.