as found calibration data e2b cal

Reading a certificate of calibration can be confusing for technicians or managers that aren’t familiar with calibration terminology. One of the most frequently asked questions is “what does as found mean?” As found is one of the key terms that are used to define measurement data. Differentiating data is important for performing comparisons and determining magnitude of any calibration drift.

As Found

The as found term refers to measurement data recorded prior to repair or adjustment. This may also be called before data or received data. As found is only used to describe measurements from an item that must be repaired or adjusted to ensure accuracy.

As Left

The term as left describes measurement data recorded after repair or adjustment. As left is often used interchangeably with the phrase after data. The as left measurement data provides validation for necessary repairs or adjustments.

Found Left

A found left term is appropriate when measurement data is recorded for an item that does not require adjustment or repair. The term found left is only used for instruments that passed testing without modification.


The inoperable term is used when an instrument is incapable of being powered on or unusable to test a specific range or function.

Why Do Terms Seem to Vary?

Managers or technicians that are new to or unfamiliar with quality processes can find the different terms confusing, leading to terms being used incorrectly. Do not mistake measurement data with instrument condition terms.

“The as found, as left, and found left terms refer to measurement data – not the instrument.”

Data Use

Comprehensive quality management systems often use the data on certificates of calibration to track tolerance conformance over time. The as found data allows managers to track calibration drift over time. This information can help quality departments make decisions about testing or tooling investments.

Example: torque wrench #003 tends to be out of calibration by more than 10% after the most recent test. The Quality Manager checks past history and finds that #003 has been testing out of calibration at a greater rate over the past 3 cycles. This may prompt the manager to shorten the calibration interval or begin planning for replacement of the wrench.Visit our Quality & Compliance Library