What is it? Why is it important?

Data entry starts after the study has been approved by EC and if applicable RA (e.g. Swissmedic) and the Site Initiation Visit (SIV) has been successfully completed.


Upon SIV:


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


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

  • Specifications given in the study protocol, including Source-Data specifications, such as
  • Data provided by participants themselves (e.g. diary, questionnaire)


What do I need to do?

As a SP-INV and Site-INV, ensure staff is trained on the collection and handling of study data, such as how to:

  • Retrieve source-data 
  • Document corrections on pCRF
  • Make certified copies
  • Manage and file study documents
  • 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)


As a SP-INV abstain from looking at or analysing the data during study conduct, as it carries a risk of corrupting the study. An exception is a planned interim analysis which is based on specifications given in the study protocol.


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 – Ethics Committee
  • eCRF – electronic Case Report Form
  • ICF – Informed Consent Form
  • ICH GCP – International Council for Harmonisation - Good Clinical Practice
  • ISF – Investigator Site File
  • IMD – Investigational Medical Device
  • IMP – Investigational Medicinal Product
  • pCRF – Paper Case Report Form
  • PIS – Participant Information Sheet
  • RA – Regulatory Authorities
  • Site-INV – Site Investigator
  • 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 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 ↦ Data Handling ↦ Data Entry ↦ Requirement

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