What is EDC in clinical trials? A plain-English guide

Every clinical trial generates data: a participant's blood pressure at visit two, whether they took the study drug, whether they had a headache. Historically, staff wrote this on paper case report forms, then someone typed it into a database. EDC removes the paper step. Staff enter values straight into an electronic form, the system checks them immediately, and the data goes into a controlled database.

Three ideas explain most of what an EDC does. First, structure: each visit has defined forms and each form has defined fields with units and types. Second, control: only authorised people can enter or change data, and every change is recorded with who, when, the old value, the new value and why. Third, cleaning: rules flag impossible or inconsistent values so they can be corrected while the participant's visit is still fresh. The longer treatment is on our EDC software page and the eCRF page; this guide covers the concepts.

CRF and eCRF. A case report form is the document that holds one participant's data for one visit; the electronic version is an eCRF. Edit check. A rule that tests entered data and creates a query when it fails. See edit checks. Query. A question about a data point that must be answered or corrected, with the resolution recorded. See query management.

SDV. Source data verification is checking entered data against the original record. Audit trail. The permanent record of every change. See audit trail software. Database lock. The point at which data are final for analysis. See database lock. ePRO. Electronic patient-reported outcomes: questionnaires completed by participants, which flow into the same study record.

Regulators expect electronic records in trials to be trustworthy. In the US that is addressed by 21 CFR Part 11, and internationally by ICH-GCP expectations on data integrity. In practice that means a computer-generated audit trail that cannot be edited, unique user accounts, role-based access, electronic signatures where used, and a documented way to show the system works as intended. Compliance is shared: the software provides controls, and your own procedures and validation make the use compliant. Capture describes its controls as 21 CFR Part 11-aligned and is hosted in the EU (Frankfurt) and the USA (N. Virginia). This is a general explanation, not legal advice. For a detailed list see the Part 11 compliance checklist and the ALCOA+ data integrity checklist.

Also look for form lifecycle control. In Capture, forms move from draft to approved, and approved forms are locked for live use, so a mid-study change is a deliberate recorded step. Calculated fields such as BMI appear read-only during entry, and per-field SDV can be set so monitors verify what matters.

Site coordinators enter visit data and answer queries. Investigators review and sign off forms where the protocol requires it. Monitors compare entered values with source records and raise queries. Data managers design checks, review data quality and prepare exports. Sponsors and project leads watch enrolment, missing data and safety events across sites. Participants may use the same system to complete questionnaires on their phone.

Because so many people touch the same record, role-based access matters. In Capture, researchers, site coordinators and admins have different permissions, site coordinators can see participant names while researchers see coded IDs, and blinded roles never receive treatment-arm values. Multi-site studies can filter and export data by site. See multi-site clinical trial management.

If you are ready to compare options, how to choose an EDC system gives a selection process, and the EDC procurement checklist covers due diligence. If you want to see what building involves, read how to design an eCRF. Capture is a self-serve platform for Phase 1 to 3 studies: you can build a full study free, test every feature, and pay only when real participants join.