Aspect | Precision | Accuracy |
---|---|---|
Definition | Precision refers to how consistent or repeatable measurements are, regardless of how close they are to the true value. | Accuracy refers to how close a measured value is to the true or accepted value. |
Focus | Focuses on the repeatability of measurements. | Focuses on how close the measurements are to the true value. |
Measurement Consistency | Measurements are consistent and close to each other, but not necessarily near the true value. | Measurements are close to the true value, but not necessarily consistent. |
Example | A dartboard example: If a person throws five darts, and they all land in the same spot but far from the bullseye, they are precise but not accurate. | If the five darts land near the bullseye (true value), but not necessarily in the same spot, they are accurate but not necessarily precise. |
Error Type | The error is random (fluctuating with each measurement), but the readings are still tightly grouped together. | The error is systematic (consistently deviates from the true value). |
Impact of Repeated Measurements | Repeated measurements will give very similar results, even if those results deviate from the true value. | Repeated measurements will vary, but the average will be close to the true value. |
Use Case | Precision is important when consistency in measurements is critical (e.g., manufacturing processes). | Accuracy is important when the correctness of measurements is critical (e.g., scientific experiments). |