Validating Measurement System Using Measurement Systems Analysis (MSA)

We frequently do not realize how our decisions depend on the results of a measurement system. We also do not adequately understand the consequences of incorrect results of a measurement system. Imagine that a doctor prescribes medicines to reduce blood pressure (BP) when it is actually normal! Doctors use BP measuring apparatus with mercury column or with a dial type gauge. If the mercury column type BP apparatus is used, it is vulnerable to “cosine error” when it is kept tilted instead of vertical. Result can artificially “increase” the BP of the person and can result in to incorrect prescription! This looks like a simple example but the incorrect decision can create major problem for the patient. In statistical terms, the doctor is making a “type I” error. Many of us may have more than one clock in our houses. We know that each clock shows a different time! This may not be a serious problem in routine decisions. However, we will not like such differences when critical decisions are made.