Language of Specifications
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What do Specifications Mean?
Hitting the mark
Specifications describe a product’s capability but some basic terms are often misunderstood. Has this dart been thrown accurately, or precisely? Is there a difference? This article explains some of the arcane language used in describing a product’s characteristics. Thumb through any instrument specification and you are presented with a whole host of technical terms describing the product’s capability. There are some basic ones which are often misunderstood, though — accuracy, precision, resolution and sensitivity spring to mind.
Basic terminology
Experience has shown that some basic metrological terms are often confused. What is the difference between accurate and precise, resolution and sensitivity, instability and noise? We’ll use some graphics to illustrate. Firstly, there are some archery or shooting targets. Four marksmen were aiming for the center “bulls-eye”. This is analogous to making a perfect measurement with the “bulls-eye” being the conventional, “true value”.