Measurements that are precise and true are accurate
- Precision is the closeness of agreement between individual test results obtained under stipulated conditions. This means: Individual test results which are close to each other are precise, while individual test results which are not close to each other are not precise.
- Trueness describes the closeness of agreement between the average of individual test results and a reference value. This means: The result is true, when the average value of individual test results is close to the reference value. And not true, when there is a high difference between average value and reference value.
Individual test results which are close to each other and in average are close to the reference value, are accurate.