What is the difference between precision and accuracy

Jump to Last Post 1-6 of 6 discussions (9 posts)
  1. scoop profile image83
    scoopposted 6 years ago

    What is the difference between precision and accuracy

  2. DreamerMeg profile image87
    DreamerMegposted 6 years ago

    I don't think there is any difference. The online dictionaries show them as synonyms of each other.

  3. Farmer Rachel profile image96
    Farmer Rachelposted 6 years ago

    In chemistry classes in college, I learned that there is a difference. Accuracy is about measurements, and how close one or more measurements is to the true value of something, i.e. can you measure 1 gram of water on your scale to be 1 gram of water exactly? Precision deals with being able to reproduce the same measurements time and again. I think I explained it correctly!!

  4. AlexK2009 profile image92
    AlexK2009posted 6 years ago

    A watch with a second hand is precise to one second. If it gains a minute a week its accuracy diminishes by one minute each week. 

    So precision tells you how closely you can measure something, accuracy telly you how close the measurement is to reality.

  5. Aficionada profile image83
    Aficionadaposted 6 years ago

    I have answered this question "accurately" from a layman's point of view. But within the fields of engineering, industry, science, and statistics, this answer is not precisely accurate!  Farmer Rachel has it right.

    There is some overlap in meaning. One of the dictionary definitions of "accurate" is "precise" - but not vice versa.

    The focus of the two words is different. The word "accurate" tends to answer an either-or question (is something correct or is it not?) and the word "precise" answers "to what degree is it correct or not?"

    As examples, (1) in the context of my family budget, I could accurately say I spent "about $10" at McDonald's. To be precise, I would say I spent $9.88.  (2) In the context of statistics related to demographics, someone could accurately say [at least, at one point in American history] that the average American family had "2 or 3" children. With numerical precision, the figure was 2.54 - as an average. But would that be "accurate"? Who has 54/100 of a child? - no, the statisticians were not talking about the unborn.

    (3) In archery, it would be accurate to say that someone hit the bull's-eye, if the arrow pierces any point within the inner ring. If the announcer or coach wants to be precise, they might say the arrow hit "dead center"; or, in another situation, they might use an exact (precise) measurement and say that the arrow hit 1.68" inside the boundary of the innermost ring.

    In mathematics, precision depends upon the degree of exactness which is being measured. Is pi more accurate taken to 100 decimal places than to 20? It is certainly more precise. But I would argue that the term accuracy would depend on the use of pi. If the answer would be rounded to the nearest 5 decimal places, then pi to 100 decimal places is no more accurate than pi to 20 decimal places.  If the calculation for some reason requires 50 decimal places, then in that situation pi to 100 places would provide the accurate answer, but pi to 20 decimal places would not.

  6. SidKemp profile image89
    SidKempposted 6 years ago

    In statistics. science, and engineering, there is a difference, and it is not explained completely clearly by any other answer. My brother and I, in writing Business Statistics Demystified (McGraw-Hill, 2004) spent two weeks writing four pages to make this clear. That's longer than we spent on some other chapters!

    What physics and engineering call precision, statisticians call reliability.
    What physics and engineering call accuracy, statisticians call validity.

    Imagine 4 archers each shooting 10 arrows at a target, aiming for the bulls-eye.

    One of them shoots all 10 arrows very close to one another, in a two-inch circle. Unfortunately, all the arrows are about 2 feet away from the bulls-eye, say, to the left. This shooter is very precise - he does the same thing every time. But he is not very accurate. He has a bias of 2 feet to the left.

    The second archer shoots all around the bulls eye - everything is in the yellow or blue, but none is in the red. Some are above the bulls-eye, others below. Some are to the right, others to the left. He is very precise - the center of all of his shooting is the center of the bulls-eye. But he is not precise enough. He needs to become more steady and reduce variability from the center.

    The third archer sends all ten arrows low, to the bottom of the target, and scattered around. He is neither precise nor accurate. He needs to become more precise by eliminating his bias (too low) and also become more accurate.

    The fourth archer lands all the arrows closely grouped in the bulls-eye, centered right at the center. He is both accurate and precise.

    In physics and engineering, we know where the target is. In statistics, we can't see the target. That's why statisticians use a different term.

    1. Aficionada profile image83
      Aficionadaposted 6 years agoin reply to this

      It is great to see this clear and complete technical explanation, but I do have a question about the sixth paragraph (the 2nd archer).  You wrote "He is very precise....But he is not precise enough."  Was that worded right or is there a slip in it?

    2. Farmer Rachel profile image96
      Farmer Rachelposted 6 years agoin reply to this

      I am confused about the second archer, too. Is he really precise at all for having missed the bullseye?

    3. SidKemp profile image89
      SidKempposted 6 years agoin reply to this

      Oops! It should have been "he is very *accurate* . . . But he is not precise enough." Thanks for catching the error.


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)