This discussion began on the Ohio Bay Specialists (OBS) LinkedIn site. So since I have the ability to edit/ clean things up here, I would like to build a decent FAQ for calibration. Hopefully, it can increase some traffic to the site. Note: This is not just my endeavor; this is a group thing. Many of the points below and such were added by others at OBS. What is calibration? The comparison of a measurement system of unverified uncertainty to a measurement system of quantified uncertainty to detect or correct any deviation from required performance specifications using standards traceable (in SI units) to an international recognized standards lab. Calibration is not to be confused with adjustment: Adjustment of a measuring system is the practice of adjusting and standardizing critical measurement equipment performance (accuracy) to appropriate traceable standards. What does “traceability” mean? What is the difference between Calibration and Verification? Does equipment used in the Design/Development process need calibrating or only for final inspection? Can I calibrate my devices in-house? What is involved? Why the 4:1 or 10:1 rule? What is "Uncertainty" and how does it influence the decision to accept/reject the Instrument based on Calibration result? What are the appropriate intervals between calibration periods? How often does it need to be calibrated? Why are most calibration frequency intervals kept to an annual cycle ? What does it mean when an instrument fails? What steps should be taken? I have a Go/NoGo gauge. Must I calibrate or verify ? Can a matching part be used as a valid verification traceability ? When do I need to have a procedure for calibration, verification ? What is the relationship, if any, between calibration and MSA What role do records have in an effective calibration program? I think once we have a good listing of the top issues, we can start writing up sections for each. I look forward to your feedback/input!