What is it? Why is it important?

Quality Data (QD) is reproducible data. In other words, data has been collected and managed in such a way that other researchers obtain similar results when repeating the study. QD means that the data is described on how it is: 

  • Generated (e.g. through blood analysis, questionnaires, medical examinations)
  • Structured (e.g. through the set-up of a study database and data files (CRF), use of standard export files and procedures, applied server)
  • Put into context (e.g. data was generated through some medical intervention)
  • Accessed (e.g. data is access protected based on user access/login rights)
  • Processed (e.g. data is explained based on its metadata, variable specifications, coding/classifications, automated processing, statistical analysis)

Providing information on data background and creation, allows data to be understood and interpreted by other researchers. This grants confidence regarding study results and its conclusions.



Example of important information needed to provide confidence in the quality of study data:

  • The context or circumstances during data collection (e.g. observational- or interventional study)
  • Methods used for data collection (e.g. blood tests, questionnaires, fitness tests)
  • The structure and organisation of data files (e.g. selection of an applicable CDMS, use of an electronic eCRF, data stored on an external server, use of back-up files)
  • Data validation and quality (e.g. based on a risk-based approach with applicable SOPs, DMP, SAP, ongoing quality checks such as data monitoring)
  • Data manipulation based on the use and analysis of raw data (e.g. automated processing)
  • Data confidentiality, database access and use conditions (e.g. restricted access to study data, use of personal password and login, identity protection by using codes rather than participant identifiers such as name, date of birth, address)

What do I need to do?

As a SP-INV generate a DMP that describes your study data and how it will be managed during study set-up, implementation, and completion.

Aspects to describe are:


For further details, include in the DMP applicable references to other quality relevant documents (e.g. SOP, WI, Quality Assurance and Quality Control aspects, risk-based QMS). In addition, inlcude main data management aspects in the study protocol.


For more information refer to Statistics and Quality and Risk in this Trial Guide.

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

  • 5.1 for QA and QC5.5. Trial Management, data handling, and record-keeping

ISO 9001:2015 – Quality Management Systems – Requirements


  • CTU – Clinical Trials Unit
  • CDMS – Clinical Data Management System
  • CRF – Case Report Form
  • DMP – Data Management Plan
  • eCRF – electronic Case Report Form
  • ICH GCP – International Council for Harmonisation - Good Clinical Practice
  • ISO – International Organization for Standardization
  • QD – Quality Data
  • QMS – Quality Management System
  • SAP – Statistical Analysis Plan
  • SOP – Standard Operating Procedures
  • SP-INV – Sponsor Investigator
  • WI – Working Instructions
Development ↦ Data Handling ↦ Data Quality ↦ Requirement

Provides some background knowledge and basic definitions

Basic Protocol
Basic Statistics
Basic Monitoring
Basic Drug or Device

Starts with a study idea

Ends after having assessed and evaluated study feasibility

Concept Protocol
Concept Statistics
Concept Drug or Device

Starts with confidence that the study is feasible

Ends after having received ethics and regulatory approval

Development Protocol
Development Statistics
Development Drug or Device

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

Starts with participant recruitment

Ends after the last participant has completed the last study visit

Conduct Protocol
Conduct Statistics
Conduct Drug or Device

Starts with last study visit completed

Ends after study publication and archiving

Completion Protocol
Completion Statistics
Completion Drug or Device
Current Path (click to copy): Development ↦ Data Handling ↦ Data Quality ↦ Requirement

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