Wikipedia:Accuracy

Accuracy is an objective of Wikipedia. This is a goal statement intended to influence the application and evolution of policies, guidelines and editorial processes which help achieve this, not to restate current policies and guidelines.

Accuracy of individual statements
The term "accuracy" is most closely associated with clear-cut situations where it means "free from error or defect", and is about a statement that may be objectively tested or confirmed using known information. In this case the meaning of the statement is so clear and objective that the meaning of the statement is not in dispute, as is whatever is used to confirm it. This requirement applies to all statements contained in each sentence. For example, "Astronaut John Smith died on December 31st, 2018" contains at least two statements; one of them (that John Smith was an astronaut) is contained as an implied premise rather than as the main operative statement of the sentence.

Accuracy is still a useful concept for other situations which are less clear-cut. Two metrics determine to what degree this is the case:
 * 1) To what degree is the meaning of the question and any responsive potential answer agreed on? For example, this agreement would be near 100% for "Who won the 2010 Super Bowl?" and near 0% for "Was Jimmy Carter a good president?" Most words have some vagueness or variability in their definitions and so the exact definitions of of terms uses must also be agreed on.
 * 2) To what degree is the answer considered to be known?

The answers to the above determine the three types of cases:


 * 1) The metrics of a correct answer are agreed on, and the answer is overwhelmingly considered to be known. For example, "Did the US land a man on the moon?" All would agree what "US land a man on the moon" means, and at least 99% of people with good access to information would agree that the answer is known to be yes.
 * 2) The meaning of the question and of a correct answer are agreed upon, but the answer is not agreed upon or known: E.g., "Where did Amelia Earhart's final flight end?"
 * 3) The metrics of a correct answer are not agreed upon, and so, of course, neither is the answer. Example: "Was Teddy Roosevelt a good president?" Even the definition / criteria of "is a good president" is not agreed upon.

For case #1, a widely accepted standard of "accurate" and "inaccurate" exists. For #2, any answer would be baseless even if not proven wrong and not considered to be accurate. For #3 the objective standard does not exist. Any answer is a value judgement and the concept of accuracy is less applicable.

A statement is also an implicit claim that the information is known, so a baseless statement is also inaccurate even if not proven false. In Wikipedia, the main mechanism to avoid both is to, rather than removing only statements proven wrong, remove any challenged statements where no policy-compliant source is provided as a basis. So Verifiability is a major help towards the accuracy goal, but does not alone guarantee it.

Re-wording with attribution is a way to convert an inaccurate or subjective statement to an accurate one. For example: "The US never landed on the moon" is inaccurate, "John Smith said that the US never landed on the moon." could be accurate. Information that is widely disputed by persons knowledgeable in that area should not be presented as fact, even if sourced.

Article level accuracy
In addition to accuracy of individual statements, it is an objective that articles provide overall accurate coverage of the topic, albeit the latter is less clear-cut. This includes balanced coverage, with inclusion weighted by degree of significance, informativeness on the topic, and directness of relevance to the topic. The article should not mislead through imbalance or omission. This requires efforts that go beyond those mandated by current policies, including emphasizing use of sources that are objective and knowledgeable in the area that they are being used.