Refer to Project Quality Management,
- Accuracy: a measure of how the measured values close to the target value
- If the measured values are accurate, they may not be precise as they can be larger or smaller than the target value on a wide range.
- Precision: a measure of how the measured values close to each other (but not necessarily close to the target value)
- If we say the measurements are very precise, we do not give out any hint on whether the measurements are accurate (i.e. close to the target value).
- Which is more important? Accuracy is MUCH MUCH MORE important than precision