Accuracy vs. Precision

If you’re familiar with archery and golf you may have heard the terms “accurate” and “precise” used interchangeably, but what do these terms really mean, and why are they important to physicists?

Accuracy is the measure of how close a trial comes to the intended result, while precision is the measure of how close together multiple trials are to each other. Accuracy deals with successes and failures in an experiment, while precision deals with a pattern made by the results of multiple consecutive trials.

A common example used by most scientists is that of throwing darts at a dartboard. Imagine that you are given fives opportunities to hit the center of a dartboard from a distance of five meters. After shooting all five of the darts it is noticed that they all landed in random places around the center of the dartboard. This would mean your ability to shoot is accurate since the darts were around the intended target, but not precise since they did not display a common pattern. If all of the darts were to land in close proximity to each other in the top right hand corner of the dartboard then your ability to shoot would be precise considering that the darts were in close proximity to each other, but not accurate considering that you missed the intended target which would have been the center.

In Physics instruments and innovations are essential to understanding and making new discoveries. In the process of making such instruments, it is essential that scientists differentiate whether the outcomes are precise or accurate in order to make the correct adjustments. If you wanted to make a robot that hit the center of the dartboard every time and you were faced with the issue that the machine was accurate but not precise you would make the needed adjustments to configure the robot to be precise and accurate as well as vice versa.

During the launches of the mars rovers physicists had to be both precise and accurate when calculating the forces acting upon the spacecrafts as they entered the atmosphere in order to avoid any consequences. Accuracy and precision are important terms to scientists and have allowed innovation and understanding to increase rapidly over time.

Picture Source: wp.stolaf.edu