What is it? Why is it important?

Database Lock (DL) is an action taken by the SP-INV upon study completion to prevent unauthorized or unintentional changes to the data after final data entry completion.

The DL is performed once:

  • All study data are entered into the study database
  • Open issues during data review, (e.g. data queries) are answered by the study site and considered resolved by the SP-INV
  • Site-INV and/or SP-INV confirm that data is complete and correct


Final DL can be faster if interim locks have already been performed during study conduct.

In addition, intermittent database locks allow the SP-INV to evaluate and analyse the data in the framework of an interim analysis in order to decide whether:

  • It is worthwhile to continue the study, (e.g. intervention shows no expected effect)
  • The study must be stopped due to ethical concerns, (e.g. treatment group performs significantly better than placebo or control group)
  • The study must be stopped due to serious safety concerns in the treatment group compared to control or placebo group

Once the database is locked the data can be exported for statistical analysis.

What do I need to do?

  • Set-up well-defined processes for database lock
  • In a multi-centre study, study sites might close their study at different time points. This must be accordingly managed by SP-INV who will perform a “global” lock once all sites meet closing criteria
  • Document the exact timing when the database was locked, in order to prove that:
    • Statistical analysis took place after the database was locked
    • The blind of your randomised blinded study was broken after database lock

Database lock should follow procedures as defined in the data management plan.


For more information refer to Data Handling in this Study Guide.


In order to facilitate database lock, plan ahead and ensure that:

  • Data entries are performed on an ongoing basis, while data is still “fresh”. Retrospective entry of large volumes of data carries increased quality risks
  • External data providers (e.g. laboratories) are informed regarding upcoming database lock in order to integrate their data into the main study database
  • Adequate time for data review and resolution of data queries is given.
  • Site-INV can sign off any complete and correct data on an ongoing basis (interim locks), so as not to postpone this task to the very end.

Where can I get help?

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


ICH GCP E6(R2) – see in particular guideline

  • 5.5. Trial management, data handling, and record keeping


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

  • 8.6 Documentation retention
  • CTU – Clinical Trials Unit
  • DL – Database Lock
  • ICH-GCP – International Council for Harmonisation - Good Clinical Practice
  • ISO – International Organization for Standardization
  • Site-INV – Site Investigator
  • SP-INV – Sponsor Investigator
Completion ↦ Management ↦ Study Closure ↦ Database Lock

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): Completion ↦ Management ↦ Study Closure ↦ Database Lock

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