We explain what accuracy is, its importance in measuring instruments and examples. Also, differences with precision.
What is accuracy?
By the word accuracy we understand, in various senses, the capacity of something or someone to be exact, that is, to be precise, accurate, punctual, to hit the target or to find exactly what is sought.
It is a word that our language inherited from Latin exactus, Participle of the verb I will demand, which is translatable as "push", "make out", "discuss" or "claim", and which in turn was composed of the voices former- ("Outward") and agere ("Perform" or "carry forward"). As will be seen, it is a word historically related to demand or demand, but which has a radically different meaning.
It is said that something is exact, thus, or that something has exactitude, when it is very similar or identical with respect to a model (be it the reality, or just a desired value), which is adequate, correct, or strictly true. In other words, 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 precisely the disease or illness that caused them.
Of course, this word has more specific meanings depending on the field in which we use it, especially when it refers to scientific disciplines. In mathematics, for example, exact operations are 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
The instruments of measurement They are tools and devices that allow expressing in numerical values any magnitude of nature, that is, to size.
These measurements, however, may contain a certain margin of error, attributable to external or contextual factors: a thermometer will always indicate the temperature body, 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.
Thus, 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 quarters 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 correct 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 his arrow hits, his 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 the engineering and in the 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:
- Accuracy has to do, as we have already said, with the closeness of the measured or recorded value to a real value. That is, how close a measurement is to reality, or in any case, to the reference value.
- Precision, on the other hand, 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 his 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 precision, that is, what margin of error his shots have in general.