During QA/QC data validation, which step involves resolving QA flags before data approval?

• A. Data completeness check.
• B. Calibrations and flow verification.
• C. Collocation results review.
• D. QA flags resolution before approval.

Answer: (D)

Resolving QA flags before approving data ensures that any data points flagged for quality concerns are addressed prior to acceptance. QA flags are raised when QA/QC checks detect potential issues such as missing or suspicious values, out-of-range measurements, or instrument anomalies. The essential step is to investigate each flagged item, determine whether the issue can be corrected or if the data should be excluded or annotated, and then re-run checks or document the rationale. Only after all flags are resolved and the data meet quality criteria should the dataset be approved. This keeps the data set trustworthy and maintains a clear audit trail.

Other steps validate different aspects: data completeness checks verify that required data exist; calibrations and flow verification confirm instrument performance at the time of measurement; collocation results review compares data to a reference method. But the step that specifically handles and closes out flagged quality issues before final approval is the QA flags resolution before approval.