What is it? Why is it important?

In studies, Source Data (SD) is the original information generated from some primary source such as a lab report, a participant questionnaire, or a medical examination.


In a study, data is generated, collected, and entered into a study database. The database is therefore not the primary data source, but contains transferred data = SD from some original record = Source Document (SDoc).


For example:

  • The patient file (e.g. medical history, x-ray reports)
  • Study specific examination documents (e.g. vital signs, height and weight, dietary habits, smoking, strength tests)
  • Medical tests and kits (e.g. blood parameters, DEXA scan, HIV test results)
  • Participant information (e.g. questionnaires, journal on the intake and handling of IMP/IMD, quality of life scores)


In order to ensure data quality, a study monitor compares SD with corresponding entries in the study database. Mistakes in the database must be corrected in order to correspond with the original SD.

where data was originally retrieved.


SD documentation is strictly regulated. Requirements includes that:

  • SD entries must comply with ALCOAC principles (e.g. attributable, legible, contemporaneous, original, accurate, and complete)
  • Copies of SDocs must be validated and certified so as to guarantee a failure free transfer of information
  • Changes to SD must remain traceable and original entries must not be obscured
  • SD entries into the study database, including potential changes, must have an audit trail that documents what entries / changes were made by whom, when, and if applicable why

What do I need to do?

Source Data are variables needed for the evaluation of the study. As a SP-INV and based on your planned study:

  • Define the variables needed for your study (e.g. age, height, weight, blood pressure, blood haemoglobin values, quality of life).
  • Define variable specifications (e.g. birth year, cm, kg, mmHg, g/dl, calculated score)
  • Define SDocs where these variables are generated (e.g. medical examination, lab report, participant questionnaire)
  • List all variables in your study protocol, or generate a Case Report Form (eCRF) that shows the set-up of your study database
  • The protocol including variables or eCRF are submitted to the Ethics Committee (EC) for approval. Changes always require EC pre-approval


In order to guarantee the quality of your data, plan quality checks that compare variables in the database with the original SD in the SDocs. For this purpose, grant easy access to monitors during the monitoring of your study.


A certified copy of a SDoc can also be defined as a SDoc, as long as the process used to generate copies has been thoroughly validated, guaranteeing a failure free transfer between the original SDoc and the generated copy.

This process might be especially useful during study archiving, where the original SDoc is not expected to remain legible during the entire archiving period (i.e. some archiving requirements are more than 20 years)

Where can I get help?

Your local CTU can support you with experienced staff regarding this topic


ICH GCP E6(R2) – see in particular guidelines

  • 1.51 Source documents definition
  • 4.9.0 Records and Reports
  • 6.10 Direct Access to Source Data / Documents

ISO 14155:2020 Medical devices (access liable to cost) - see in particular sections

  • 7.5.3 Source documents
  • 7.8 Document and data control
  • g Monitoring
  • ALCOAC - Attributable Legible Contemporaneous Original Accurate, Complete
  • CRF – Case Report Form
  • CTU – Clinical Trials Unit
  • EC – Ethics Committee
  • EC/RA – Ethics committee / Regulatory Authorities
  • ICH-GCP – International Council for Harmonisation - Good Clinical Practice
  • ISO – International Organization for Standardization
  • SD – Source Data
  • SP-INV – Sponsor Investigator
Development ↦ Management ↦ Study Documents ↦ Source Data

Provides some background knowledge and basic definitions

Basic Monitoring
Basic Drug or Device

Starts with a study idea

Ends after having assessed and evaluated study feasibility

Concept Drug or Device

Starts with confidence that the study is feasible

Ends after having received ethics and regulatory approval

Development Drug or Device

Starts with ethics and regulatory approval

Ends after successful study initiation

Set-Up Ethics and Laws
Set-Up Quality and Risk
Set-Up Drug or Device

Starts with participant recruitment

Ends after the last participant has completed the last study visit

Conduct Drug or Device

Starts with last study visit completed

Ends after study publication and archiving

Completion Statistics
Completion Drug or Device
Current Path (click to copy): Development ↦ Management ↦ Study Documents ↦ Source Data

Please note: the Easy-GCS tool is currently under construction.