Measurement
Accuracy & precision
Same target every shot? Or close to bullseye? They're different things.
Accuracy is how close you are to the true value. Precision is how consistently you get the same value. They're not the same thing.
Bullseye every time = accurate AND precise. Tight cluster off-target = precise but inaccurate. Scattered around bullseye = accurate but imprecise. Scattered all over = neither.