Tell me more ×
Cross Validated is a question and answer site for statisticians, data analysts, data miners and data visualization experts. It's 100% free, no registration required.
up vote 0 down vote favorite

Is precision a "quality" of a measurement?

Is there a better (accepted by the literature) word?

share|improve this question
As the disambiguation page on wikipedia demonstrates, precision is an ambiguous term. Can you put it into context? – Björn Pollex Mar 21 '11 at 12:17
@John Precision in what sense? For example, reliability of scores will probably have a different meaning in Psychometrics, depending on the model we consider, as compared to other scientific fields. – chl♦ Mar 21 '11 at 12:25
Precision as the "quality" that assures that repeated measurements (on the same subject) will lead to the same result. – John Assymptoth Mar 21 '11 at 13:43
@John The NIST is the authority on such issues. Its guidance is comprehensive and clear: physics.nist.gov/Pubs/guidelines/appd.1.html . (For the record: the NIST prefers not to use "precision" but accepts it when used with disambiguating language. See D.1.2.) – whuber♦ Mar 21 '11 at 14:08
1  
@John This sounds like a question more suitable for the 'english' SE site. I think the NIST would say precision is a quality, characteristic, attribute, feature, or property of the measurement process, not of the measurement itself (much as "painful" might describe the creation of a work of art but--one hopes--does not apply to the art work itself!). As far as English usage goes, both "quality" and "characteristic" tend to invoke a sense of being inherent or essential whereas "attribute," "feature," and "property" are more generic. Which to use depends on what you want to emphasize. – whuber♦ Mar 21 '11 at 15:01
show 6 more comments

closed as off topic by whuber♦ Mar 21 '11 at 21:27

Questions on Cross Validated are expected to relate to statistics within the scope defined in the FAQ. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about closed questions here.

2 Answers

up vote 0 down vote

I believe it's only one aspect of a quality of measurement, an other is known as accuracy. Precision and accuracy are not the same thing. I always think about it as a bell curve, the position of the mean is accuracy, the spread from the mean is precision

share|improve this answer
up vote 0 down vote

In the first statistics class I ever took, a darts analogy was used. If you have a bunch of darts around the bullseye but fairly spread out you have an accurate but imprecise landing position, whereas if you have a bunch of darts tightly clustered around some other position be it the wall or somewhere on the dartboard you have a precise but inaccurate landing position.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.