What is it? Why is it important?

Study data entry can start after the study has been approved by EC/RA and the Site Initiation Visit (SIV) has been successfully completed.

Upon SIV:

  • The database (eCRF) is ready for data entry with staff given individual access rights (documented in a database access log)
  • Required study material has been delivered to the study site such as:
    • Drug or device under investigation (IMP/MD)
    • Laboratory equipment (e.g. serum tubes, analytical device)
    • Study documents (e.g. patient questionnaires, study protocol, PIS, ICF, ISF essential documents, study SOPs and WIs, checklists)
  • Staff is trained on study tasks and individual responsibilities


Type of study data to be collected must be based on:

  • Specifications given in the study protocol
  • Source-data as defined in the study protocol and retrieved from participant’s
    • Medical record
    • Laboratory results
    • Medical examinations
  • Data provided by participants themselves (e.g. diary, questionnaire)

During study conduct the SP-INV must abstain from looking at or analysing study data, which carries the risk of corruption. An exception would be a planned interim analysis with its specifications documented in the study protocol

What do I need to do?

Ensure staff is trained on the collection and handling of study data such as:

  • What source-data to collect and where this data can be retrieved
  • How to document corrections on pCRF
  • How to make certified copies
  • How to file and store collected study documents (e.g. pCRF, participant questionnaires, medical interviews)
  • Respect participant confidentiality:
    • Use of participant code instead of personal identifiers
    • Ensure restricted access to study hard copies (e.g. participant study folders and information)

Only once participants have been adequately informed about the study and agreed to participate by signing the study ICF can data collection begin.


For more information refer to Monitoring in this Study Guide.


When making corrections on pCRF, the following guidelines must be followed:

  • Only study staff with documentation responsibilities can make corrections on study documents
  • Original entries must remain legible
  • Corrections are dated and initialised so as to trace any correction in case further clarifications are needed

In the electronic database (eCRF), entries and changes to data are automatically documented in the audit trail of the system.

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

  • 5.5. Trial Management, data handling, and record-keeping
  • CTU – Clinical Trials Unit
  • EC/RA – Ethics Committee / Regulatory Authorities
  • ICF – Informed Consent Form
  • ISF – Investigator Site File
  • pCRF – Paper Case Report Form
  • PIS – Participant Information Sheet
  • SIV – Site Initiation Visit
  • SOP – Standard Operating Procedures
  • SP-INV – Sponsor Investigator
  • WI – Working Instructions
Conduct ↦ Data Handling ↦ Data Entry ↦ Requirement

Provides some background knowledge and basic definitions

Basic Protocol
Basic Statistics
Basic Monitoring
Basic Drug or Device
Basic Biobanking

Starts with a study idea

Ends after having assessed and evaluated study feasibility

Concept Protocol
Concept Statistics
Concept Drug or Device
Concept Biobanking

Starts with confidence that the study is feasible

Ends after having received ethics and regulatory approval

Development Protocol
Development Statistics
Development Drug or Device
Development Biobanking

Starts with ethics and regulatory approval

Ends after successful study initiation

Set-Up Protocol
Set-Up Ethics and Laws
Set-Up Statistics
Set-Up Quality and Risk
Set-Up Drug or Device
Set-Up Biobanking

Starts with participant recruitment

Ends after the last participant has completed the last study visit

Conduct Protocol
Conduct Statistics
Conduct Drug or Device
Conduct Biobanking

Starts with last study visit completed

Ends after study publication and archiving

Completion Protocol
Completion Statistics
Completion Drug or Device
Completion Biobanking
Current Path (click to copy): Conduct ↦ Data Handling ↦ Data Entry ↦ Requirement

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