Data clarification form

A Data Clarification Form (DCF) or Data Query Form (DQF) is a questionnaire specifically used in clinical research. The DCF is the primary data clarification tool from the trial sponsor or Contract Research Organization (CRO) towards the investigator to clarify discrepancies and ask the investigator for clarification. The DCF is part of the data validation process in a clinical trial.

In clinical trials, the data validation step and asking the investigator for clarification of discrepancies (data cleaning) is an important step towards creating a clean dataset suitable for statistical analysis of the clinical trial outcome.