As-Found Data

As-found data captures the true state of an instrument at the time of calibration, documenting how it was actually performing during the period since its last calibration. This data is recorded before any adjustments, cleaning, or corrections are made. It is the most important data in the calibration process because it reveals whether the instrument was providing accurate measurements while in service.

Recording as-found data is critical for assessing the reliability of measurements made since the last calibration. If the as-found data shows the instrument was within tolerance, there is confidence that measurements made during the calibration interval were valid. If the instrument is found out of tolerance (OOT), an investigation is triggered to determine the impact on products, processes, or test results that depended on the instrument's measurements.

For calibration management, as-found data serves multiple purposes. It provides the basis for OOT notifications and impact assessments. It is the primary input for calibration interval optimization — trends in as-found data across multiple calibration cycles reveal instrument stability and drift patterns. Statistical analysis of as-found data across a fleet of similar instruments can identify systematic issues (bad lot, design defect, environmental problem). Quality systems like ISO 9001, ISO 17025, and AS9100 all require as-found data to be recorded and retained as part of calibration records.