Measurements
Clinical instrument…
- … is valid if it produces an average measure of the outcome of
interest
- … is reliable if it produces similar scores in similar situations.
Lab instrument
- A measure is accurate if it produces an average estimate of the
quantity of interest
- A measure that is not accurate is biased.
- A measure is precise if it produces very similar outcomes under
similar circumstances.
- A measure that is not precise has high variability.