Introduction Reporting measurement uncertainty in test and calibration certificates is a common practice for ISO/IEC 17025 accredited laboratories. It is also a common problem for a lot of laboratories. Many struggle to do it right. Most accredited laboratories are required to include uncertainty in their certificates. However, many of them do not know how […]
Introduction Ever wondered what factors are significant contributors to uncertainty in measurement? Are you performing an uncertainty analysis and wondering what components to include in your uncertainty budget? Maybe an assessor cited you a deficiency and recommended that you include more sources of uncertainty in your budgets. Afterward, they provided you with a laundry […]
Key Takeaways Type A Evaluation: Methods based on the statistical analysis of a series of observations (Repeatability, Reproducibility). Type B Evaluation: Methods based on means other than statistical analysis (Calibration reports, specs, history). Purpose: The distinction is based on the *method of evaluation*, not the nature of the uncertainty itself. Consistency: Both types are expressed […]
Introduction A laboratory’s scope of accreditation is a key element of ISO/IEC 17025 accreditation and a vital asset to your customers. It lists all of the activities that your laboratory is accredited perform. However, many laboratories forget to consider its importance when getting accredited or reaccredited. They just rush to develop a scope of […]
Introduction Estimating uncertainty can be a difficult task, especially if you are a beginner. Tools like an uncertainty budget or calculator can really make a big difference. However, software to calculate uncertainty is typically outdated, expensive, and difficult to learn. Many people have problems because they do not know what to do or where […]
Introduction Reproducibility testing is an important part of estimating uncertainty in measurement. It is a type A uncertainty component that should be included in every uncertainty budget. However, a lot of laboratories neglect to test reproducibility and include it in their analyses. When talking with clients and friends, I get a lot of reasons […]
Key Takeaways: Sensitivity Coefficients Definition: A multiplier that describes how the output estimate (y) changes with variations in an input quantity (xi). The Calculus: Mathematically defined as the partial derivative of the measurement function with respect to the input variable (δf / δxi). Purpose: Used to convert all uncertainty components into the same units as […]
Introduction One the most difficult things about calculating uncertainty in measurement is finding sources of uncertainty. It is a process that can require you to conduct hours of research. Seriously! You could waste hours of your life researching sources of measurement uncertainty. It can be even worse if you have no idea where to look […]
Introduction Need a measurement uncertainty calculator? If are an ISO/IEC 17025 accredited laboratory, it is in your best interest to have software for estimating measurement uncertainty. Additionally, if you are like me, you have most likely searched online for uncertainty calculator software. Did you find measurement uncertainty software that you like to use? If so, […]
Introduction Calculating uncertainty in measurement can be difficult. Especially, now that you are required to calculate the uncertainty for every measurement result in your calibration reports. For years, many laboratories have just included a statement of uncertainty hidden in the small print of their reports that only provide the CMC Uncertainty statement published in their […]
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