What is it? Why is it important?

Source data (SD) is contained in source documents, which are the first place where any original information is initially recorded. In other words, where data is first documented or where physical information is first digitised.


In studies, SD are original records from which data is gathered and entered into the study database (eCRF). Thus, SD:

  • Provides the data needed to answer a study question(s)
  • Is accessed during study monitoring, in order to countercheck data entered in the study database (e.g. eCRF) against its original source. Only if both entries are identical, can it be confirmed that the transfer between SD and eCRF was correctly performed. This process is called Source Data Verification (SDV)


Example of SD:

  • Hospital / medical records (e.g. patient files)
  • Laboratory reports
  • Participant diaries and questionnaires
  • Evaluation checklists
  • Pharmacy dispensing records
  • Data digitised from automated instruments
  • Certified copies of microfiches, photographic negatives, microfilm, magnetic media, x-rays


Having robust source documents is vital for the quality of the study. Therefore they need to fulfil certain characteristics:

  • Attributable - it must be clear to which participant they belong
  • Legible - they must be readable
  • Contemporaneous - they must be noted immediately after the data is generated
  • Original - they must be the original
  • Accurate - they must be reliably correct.
  • Originator information – who entered the data and when
  • If data are collected via an electronic mean, the machine (and software) must be identifiable and be calibrated and validated


Any data collected from study participants require initially be approved by EC and RA (e.g. Swissmedic). Thus, all data that is collected during study conduct must be listed and described in the study protocol.


Once approved:

  • Only SD data listed in the study protocol can be collected
  • The collection of SD not specified in the study protocol, require a prior protocol amendment and prior EC/RA approval

What do I need to do?

As a SP-INV or Site-INV:

  • Make a list (called SD location form) of any collected SD (based on study protocol)
  • Define SD location to ensure correct data retrieval (e.g. laboratory reports, patient file)
  • Ensure SD:
    • Is entered in a timely manner in the study database (eCRF/pCRF)
    • Remains at the site and is not externally transferred or accidently destroyed
  • Provide access to the study databse and its SD during study monitoring


Abstain from entering data directly into the eCRF, thereby bypassing SD documentation. SDV will consequently no longer be possible.


Handling of SD:

  • Date and sign study related SD
  • File any collected SD according to SD the correct location in the PF (e.g. lab reports)
  • In the event information is entered by hand, ensure data is correct, complete and legible
  • In paper PF, date and sign changes and ensure that original entries remains legible


Quality control and SDV verification:

During study monitoring, the monitor checks whether data entered in the study eCRF or in the pCRF corresponds to the original information provided in SD. All errors in pCRF or eCRF must be corrected (e.g. sign and date any corrections and ensure deleted pCRF entries remain legible)

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 Data
  • 1.52 Source Documents
  • 4.9.0 Source Data Records and Reports
  • CRF – Case Report Form (p – paper; e – electronic)
  • CTU – Clinical Trials Unit
  • EC/RA – Ethics Committee / Regulatory Authorities
  • eCRF – electronic Case Report Form
  • pCRF – Paper Case Report Form
  • PF – Patient File
  • SD – Source Data
  • SDV – Source Data Verification
  • Site-INV – Site Investigator
  • SP-INV – Sponsor Investigator
Conduct ↦ Documents ↦ Required 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): Conduct ↦ Documents ↦ Required Documents ↦ Source Data

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