We explain what accuracy is, its importance for measuring instruments and examples. Also, differences between accuracy and precision.
What is accuracy?
By the word accuracy we understand, in different senses, the capacity of something or someone to be exact, that is, to be accurate, punctual, hitting the target or reaching exactly to what one is looking for.
It is a word that our language inherited from the Latin modular word “accuratus“, a combination between between “ad” (“towards“) and “cura” (“care“). As will be seen, it is a word historically related to care, with a bit of a radical meaning.
It is said that something is accurate, like this, or that something has accuracy, when it is very similar or identical with respect to a model (be it reality, or simply a desired value), that it is adequate, correct or rigorously true. In other words, the accuracy has to do with the proximity of a thing to the truth.
For example, if we paint a portrait exactly the same as your model, we are saying that it is as close as possible to the original; or if we say that a medical diagnosis turned out to be exact, we are affirming that from the reading of the patient’s symptoms, he found accurately the disease or ailment that caused them.
Of course, this word has more specific meanings depending on the area in which we use it, especially when it comes to scientific disciplines. In mathematics, for example, accurate operations are known as those that result in a whole number, that is, without decimal parts.
This same criterion is applied in practice in the financial sphere: “paying the exact amount” means that we must pay in such a way that we neither exceed the money offered, nor do we fall short, but rather that we must deliver the right amount.
Accuracy in measuring instruments
Measuring instruments are tools and devices that allow expressing some magnitude in numerical values of nature, that is, measure.
These measurements, however, may contain a certain margin of error, attributable to external or contextual factors: a thermometer will always indicate body temperature, but it may do so with a certain margin of proximity, that is, it may register a value close to the real one. To the extent that said value is more similar to the real one, we can say that it is more or less exact, that is, that it has greater or lesser accuracy.
A) Yes, some instruments have greater margins of error than others, that is, they have greater or lesser accuracy. A tape measure, manufactured according to international standards of how long a meter is, will undoubtedly offer us greater margins of accuracy than if we measure the same object using the fourths of a hand: the approximate values are, logically, very inaccurate, and that is why This is why in science and engineering accuracy is preferred.
Examples of accuracy
Some examples to illustrate the notion of accuracy are the following:
- A furtive lover throws stones at the window of his beloved, so that she looks out and they can be seen on the sly. If your stones hit the right window, you will have made the shot exactly.
- An archer draws his bow to try to hit the target, and depending on how close to the center your arrow hits, its accuracy can be measured.
- A doctor must diagnose a disease from a set of symptoms. If you can find the correct disease, your analysis will have been accurate. If instead it is a similar but different disease, it will have been less accurate when diagnosing.
Precision and accuracy
In the scientific world, in engineering and in statistics, the notion of accuracy is usually distinguished from that of precision, although in everyday speech it is possible to use them as synonyms. The difference between the two is important in understanding and interpreting experimental results or measurements, and depends on the following:
- The accuracy it has to do, as we have already said, with the proximity of the measured or registered value with respect to a real value. That is, how close a measurement is to reality, or in any case, to the reference value.
- Precision instead, it has to do with the ability of an instrument or a technique to record similar values in successive measurements, since these may vary depending on the margin of error, that is, on certain variables in the context.
This difference can be more easily understood with an example. Suppose a golfer tries to make a hole in one to break a local record. He is a good golfer, but no matter how good his technique is, there are variables that influence each shot: the wind, the humidity, the perfection of the golf ball or the force that he puts into the shot; so you will have to try many times until you finally achieve it.
Well, if we judge how close to the hole their balls have landed, we will find the measure of its accuracy, since we know that the reference value is the hole itself. On the other hand, if we compare the number of times that his shots were close to the hole, against the total number of attempts made, we can find his accuracy, that is, what margin of error his shots have in general.