Measuring Work Accurately Available to Purchase

It seems so obvious that, when we measure something, we need to measure it accurately. But is it really true? Sometimes a rough and ready estimate is all we need to enable us to make a decision. In fact there are a number of terms (such as precision and reliability) that crop up to describe measurements and we need to be sure that we understand the relationships between these terms and their impact on choosing an appropriate measurement system for a given job.