What’s the difference between accuracy and precision? – Matt Anticole
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What’s the difference between accuracy and precision? – Matt Anticole

August 15, 2019


As the story goes,
the legendary marksman William Tell was forced into a cruel challenge
by a corrupt lord. William’s son was to be executed unless William could shoot
an apple off his head. William succeeded, but let’s imagine
two variations on the tale. In the first variation, the lord hires a bandit to steal
William’s trusty crossbow, so he is forced to borrow
an inferior one from a peasant. However, the borrowed crossbow
isn’t adjusted perfectly, and William finds that his practice shots cluster in a tight spread
beneath the bullseye. Fortunately, he has time
to correct for it before it’s too late. Variation two: William begins to doubt his skills
in the long hours before the challenge and his hand develops a tremor. His practice shots still cluster
around the apple but in a random pattern. Occasionally, he hits the apple, but with the wobble,
there is no guarantee of a bullseye. He must settle his nervous hand and restore the certainty in his aim
to save his son. At the heart of these variations
are two terms often used interchangeably: accuracy and precision. The distinction between the two is actually critical
for many scientific endeavours. Accuracy involves how close you come
to the correct result. Your accuracy improves with tools
that are calibrated correctly and that you’re well-trained on. Precision, on the other hand, is how consistently you can get
that result using the same method. Your precision improves
with more finely incremented tools that require less estimation. The story of the stolen crossbow
was one of precision without accuracy. William got the same wrong result
each time he fired. The variation with the shaky hand
was one of accuracy without precision. William’s bolts clustered
around the correct result, but without certainty of a bullseye
for any given shot. You can probably get away
with low accuracy or low precision in everyday tasks. But engineers and researchers
often require accuracy on microscopic levels with
a high certainty of being right every time. Factories and labs increase precision through better equipment
and more detailed procedures. These improvements can be expensive,
so managers must decide what the acceptable uncertainty
for each project is. However, investments in precision can take us beyond
what was previously possible, even as far as Mars. It may surprise you that NASA
does not know exactly where their probes are going to touch down
on another planet. Predicting where they will land
requires extensive calculations fed by measurements
that don’t always have a precise answer. How does the Martian atmosphere’s density
change at different elevations? What angle will the probe
hit the atmosphere at? What will be the speed
of the probe upon entry? Computer simulators run thousands
of different landing scenarios, mixing and matching values
for all of the variables. Weighing all the possibilities, the computer spits out
the potential area of impact in the form of a landing ellipse. In 1976, the landing ellipse
for the Mars Viking Lander was 62 x 174 miles,
nearly the area of New Jersey. With such a limitation, NASA had to ignore many interesting
but risky landing areas. Since then, new information
about the Martian atmosphere, improved spacecraft technology, and more powerful computer simulations
have drastically reduced uncertainty. In 2012, the landing ellipse
for the Curiosity Lander was only 4 miles wide by 12 miles long, an area more than 200 times
smaller than Viking’s. This allowed NASA to target
a specific spot in Gale Crater, a previously un-landable area
of high scientific interest. While we ultimately strive for accuracy, precision reflects our certainty
of reliably achieving it. With these two principles in mind, we can shoot for the stars and be confident
of hitting them every time.

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  1. Accuracy is the ability to hit the bull's eye., precision is having a result being close to one another without actually hitting the bull's eye

  2. Thank you. This another ahuh moment for me. So @1:30:
    Accuracy – how close you get to the target.
    Precision – the concistency of your hits on the target.

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  4. – Precision and consistency are two different things.
    – How accurate is how off from perfection.
    – Being precise is not having any other possible alternative.

  5. T҉h҉e҉ ҉D҉a҉w҉n҉ ҉R҉i҉g҉h҉t҉ ҉B҉e҉f҉o҉r҉e҉ ҉ T҉h҉e҉ ҉S҉u҉n҉-҉R҉i҉s҉e҉ ҉I҉s҉ ҉T҉h҉e҉ ҉D҉a҉r҉k҉e҉s҉t҉ says:

    How correct can you get it? = Accuracy
    How often can you get it correctly? = Precision

  6. You hace 6 bullets. Your a terrorist.
    Your goal is to make head shots on the forehead.
    Action: you start shooting at running people
    Accuracy: whether you hit the person or not.
    Percision: how many times youve hit a person on the forehead

    Percision is like statistics. It measures multiple things. If you only have one input and output there is no percision because percision compares or averages the accuracy of another.

    1 A human is a donut
    2 A human is made of atoms
    3 A human is human

    The accuracy of 1 is just simply completely off.
    2 and 3 are correct.

    Percision measures the 3.
    Or it measures specific numbers.
    Like comparing 1 to 3. Or comparing 2 to 3.

    One compares and measures accuracy of something forming a /frequency (percision)

    The other is simply the action or thing thats being measured as how accurate something is.

    Percision doesnt measure accuracy.
    Compares and averages accuracy.

    Another one.

    Accuracy- 10kids guess an answer. 9 are wrong. 1 is correct.

    Percision- averages all the kids inputs on what the answer is to a question. Output: [correct/incorrect]
    The percision of the group of kids answer is 10%.

    Or you could get more complex. Who's closer to being correct out of the incorrect students.

  7. I watched this video 3 times in 2 years now and I still don't understand. Maybe, because such a problem does not exist in my native language, german

  8. Its sad and pitiful how some people get hyped by these youtube money generating TED talks assuming they are authoritative and precise.

    Almost all my PAPER thesauruses post Accurate and Precise as almost absolute synonyms and they are authoritative as a book can be. This video gives a wrong context to the word Precision. To repeat an accurate or precise or any other required result is : consistency NOT precision. In Engineering terms ACCURACY AND PRECISION are synonyms. To repeat a precise – accurate result is an act of consistency and whoever post this video gives a false meaning unless the video “suggests” a possible synonymity between Precision and Consistency. Please state : source, textbook and author in Oxford Referencing style that supports the argument of this video.

  9. So
    Precision = accuracy
    Accuracy =/= precision
    Kinda like how a rectangle is a square but a square is not a rectangle.

  10. so uhhh basically accuracy is the result of precision?

    precision is based on the person?
    while accuracy is based on the crossbows calibration?

  11. I'm just gonna say what I learnt in class:-

    Accuracy: how close the result or average of results is to actual value.

    So peak of occurrence graph is on actual value

    Precision: how close every result is to other.

    So occurrence graph has a steep peak.

    Also low accuracy means high systematic error and low precision means high random error

  12. Learn it in short.
    Accuracy- how close you hit the target
    precision- how many times you can hit a target with same consistency as before

  13. So in gamer talk it’s like having a pc and aiming really good and all but then it broke and you have to play on a ps4 with keyboard and mouse with input lag and some buttons not processing

  14. I can answer this without the video.

    Accuracy is the closest you can get to a specific target or goal. If a statement is accurate, It is closest to the truth.

    Precision is the AMOUNT of times you can be consistently accurate. If you make 6 back-to-back factual statements in a debate or argument. That is precise. That is consistent accuracy towards a goal or topic.

  15. Google defines these two terms by using them within the definition of each other. Like what??? Precision is being accurate and accuracy is being precise

    Yah Im done with you google dictionary

  16. Basically
    Accuracy: Deviation.
    Precision: Standard Deviation.
    I haven't watched the video but did I get that right?

  17. Accuracy is being in the right ballpark, but you didn't fuss with the minutia. Precision is dotting the i's and crossing the t's, but you could be in the wrong ballpark.

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