How to Calculate Load Cell Specific Risk Step-by-Step Instructions Many people struggle with decision rules and how to calculate risk. This article provides step-by-step instructions to calculate Measurement Uncertainty, Guard Band Acceptance Limits, and Probability of False Acceptance (PFA). Load Cell Specific Risk Example Calculation: To Calculate PFA, the Excel function is NORM.DIST. Risk upper […]
Guarded rejection: 1 Valuable Tool for Reducing the Risk of False Rejection When assessing the conformity of a product or service to a specified requirement, it is crucial to have a high degree of confidence in the decision. This is especially true when the consequences of a false rejection or false acceptance are high. Guarded […]
A Simplified Global and Specific Risk Example A company has hired us to measure the speed of cars on a stretch of a single-lane road. The customer wants options using both Global and Specific Risk examples as they are unsure what method will give them what they need to meet the specification as they know […]
Understanding Global Risk in Simple Terms In the world of engineering and product design, there's a concept that Henry Petroski discusses in his book, "To Engineer is Human: The Role of Failure in Successful Design." He suggests that engineers and companies might become complacent when things are going well. They might not take the necessary […]
Delving into Specific Risk: A Comprehensive Understanding of PFA and PFR Specific risk in metrology, mainly focusing on the Probability of False Acceptance (PFA) and Probability of False Rejection (PFR). These concepts are crucial in the decision-making process based on measurement results. Specific Risk Specific risk, as the term suggests, is a risk that is […]
A Simplification of the Differences Between Specific and Global Risk Understanding the Differences Between Specific and Global Risk is a complex topic. For this article, we are going to explain the difference between specific and global risk without getting into too much detail. In metrology, risk is a crucial factor influencing the decision-making process based […]
Decision Rules - Our Top 10 Recommended Reading Many people struggle with decision rules and implementing decision rules. At Morehouse, we have been privileged to be part of the Metrology Handbook 3rd Edition, where we helped write a chapter on decision rules. Though it was an honor to write that and other chapters, there are […]
What can happen when we use an accuracy specification and assume all the measurements are centered in relation to the specification limits? It is a typical problem in the metrology community, where many papers assume a centered process or Measurement. When the Measurement deviates from the true value, it is said to have a bias […]
The New Dimension to Resolution: Can it be Resolved? Our last blog, Device Resolution and the Impact on Consumer Risk, described why best practices should be followed for conformity assessments rather than drafting individual test protocols and standards. How should manufacturers and calibration laboratories correctly calculate both uncertainty and risk on equipment? Risk, Conformity Assessment, […]
Device Resolution and the Impact on Consumer Risk - Intro If a device's uncertainty has too coarse of a resolution, then you need a device that does not subject the conformance decision to higher risk. This blog will present examples that demonstrate why best practices should be followed for conformity assessments rather than drafting individual […]
Specifying a Tolerance, the Difference Between Percentage of Indicated Value vs % of Full-Scale Output - Intro In looking at various equipment, it seems the force equipment in the test and measurement industry specifically specifies tolerances as a percent of full scale. When determining accuracy or tolerance, several crane scales, tension links, and hand-held force […]
Why a 4:1 TUR is Not Enough: The Importance of Analyzing the Probability of False Accept Risk Figure 1 Graph Showing Method 5 Acceptance Limits Several organizations and publications reference the use of a 4:1 Test Uncertainty Ratio (TUR). Some standards even reference a TUR requirement greater than or equal to 4:1. The question to […]
