Wikipedia:Verifying different types of statement

The policy on verifiability is clear that the criterion for inclusion in Wikipedia is verifiability, not truth. The policy also implies that different types of statement require different types of verification. It says that material that is challenged or likely to be challenged, and all direct quotations require an inline citation to a reliable source and that exceptional claims require exceptional sources. This essay develops this concept further and presents the views of some editors on what is required to verify different types of statement in Wikipedia.

Four types of statements
1. Is the matter one of ascertainable fact? Such facts are, by definition, non-contentious. "A U.S. quarter is one inch in diameter." Almost any source is good enough to be sure on these.

2. Is the matter one of contentious fact? a) "John Doe was arrested for DUI" is in this category. If it is for a BLP, then the source should be a fully reliable source, not tainted in any way, and not part of anything remotely considered an "opinion piece." b). "AGW has been proven". Requires reliable sources which are not initial studies of one aspect of the issue, précis from newspapers based on such studies, or government documents which do not make the simple statement for which they are used as a cite, but which are ideally subjected to rigorous fact-checking, either through a peer-review process for scientific studies, or through an editorial process which verifies facts before publication. "Governmental reports" which are one step removed from the hands of peer-review are now especially reliable for such statements of fact ("The Stimulus saved or created 800,000 jobs" is such an example.)

3. Is the matter one of opinion? a). Opinions of notable people must be cited to either a reliable source as in 2b, or to material under their own control (thus self-published opinions should be usable as opinions of the person who publishes them). b). Opinions of non-notable people can only be cited in aggregate, and only where the reliable source makes the connection as to the aggregate.

4. Gossip is not usable no matter the source. No matter how juicy. No matter how many tabloids have covered it.

The purpose of sources is not to show how many references one can fit into an article (see WP:Citation overkill), but only to be sufficient to back up claims made in any article. As much as possible, articles should deal with simple facts, though this is not always possible. Where opinions enter into an article, it is essential that sources be used accurately, and that material from them be described as opinions. It is better to have a short, accurate article than to have a long article stuffed with opinions added to achieve some sort of neutrality by having lots of opinions on all sides.

And always remember that it is the task of editors to produce high-quality articles based on the reasoning of others who are authorities in a field. It is not up to editors to "know" what the truth is for an article.

Requirements and Standards for Reference Citing
This essay will develop guidelines and information under each of the following items. Where this has not yet been done for an item, please use the most relevant Wikipedia guideline.

The required "strength" of reference citing for a statement varies with the nature of the situation
If uncontested, the required strength is "low" "Low could even include "none” if both uncontested and unquestioned. The author MAY put in a statement where they know of no references to support it, but then it should be removed if there is a good faith question or challenge of its correctness or accuracy.

If contested, but NOT in a heated or acrimonious area, the standard is "medium" A typical example of this a friendly exchange on a matter of fact where one person feels that the other made an error.

If contested, and in a heated or acrimonious area, the standard is "high" A typical example of this is where there is a political battle going on elsewhere on an issue or topic, and the sides are seeking to have the article subtly or blatantly advance their "side", or where the article has become merely a place for them to do battle.

The standard is also "high" when there is an unresolved disagreement regarding the statement.

The "strength" of an editor's citing of reference for a particular statement is determined by a combination of these items:
The degree that it directly and fully supports the WP editor's statement which cited it This is the opposite of Original Research.

The degree that what the reference on that topic is representative of what the available references say This is the opposite of "cherry picking” an unrepresentative reference.

The Primary/Secondary/Tertiary attribute of the reference Definitions of these are as follows:


 * Primary sources are very close to an event, often accounts written by people who are directly involved, offering an insider's view of an event, a period of history, a work of art, a political decision, and so on. An account of a traffic accident written by a witness is a primary source of information about the accident; similarly, a scientific paper is a primary source about the experiments performed by the authors. Historical documents such as diaries are primary sources. Further examples include archaeological artefacts, census results, video or transcripts of surveillance, public hearings, trials, or interviews; tabulated results of surveys or questionnaires; original philosophical works; religious scripture; and artistic and fictional works such as poems, scripts, screenplays, novels, motion pictures, videos, and television programs. For definitions of primary sources:

The University of Nevada, Reno Libraries define primary sources as providing "an inside view of a particular event". They offer as examples: original documents, such as autobiographies, diaries, e-mail, interviews, letters, minutes, news film footage, official records, photographs, raw research data, and speeches; creative works, such as art, drama, films, music, novels, poetry; and relics or artefacts, such as buildings, clothing, DNA, furniture, jewellery, pottery. The University of California, Berkeley library offers this definition: "Primary sources enable the researcher to get as close as possible to what actually happened during an historical event or time period. Primary sources were either created during the time period being studied, or were created at a later date by a participant in the events being studied (as in the case of memoirs) and they reflect the individual viewpoint of a participant or observer."


 * Secondary sources are second-hand accounts, at least one step removed from an event. Secondary sources write about primary sources, often making analytic or evaluative claims about them. University of California, Berkeley library defines "secondary source" as "a work that interprets or analyzes an historical event or phenomenon. It is generally at least one step removed from the event". For example, a review article that analyzes research papers in a field is a secondary source for the research. The Ithaca College Library compares research articles (primary sources) to review articles (secondary sources).


 * Tertiary sources are publications such as encyclopaedias or other compendia that mainly summarize secondary sources. Wikipedia is a tertiary source. Many introductory undergraduate-level textbooks may also be considered tertiary sources, to the extent that they sum up multiple secondary sources.

"Secondary" sources rate the highest in this category.


 * The authoritativeness and objectivity of the reference regarding the topic This is not limited to traditional academic definitions. For example, a credible claim of firsthand knowledge and objectivity might suffice.


 * Whether or not it is done by an in-line citation An in-line citation invoking a reference is stronger referencing. Not only is it more informative, it is also a reviewable claim by the writer that the cited reference supports the statement.


 * The number of references cited to support the statement The above questions apply to each of them.

Implementation of these guidelines
The thoroughness of the process to make these determinations should be as light as there is a consensus for. When in doubt, approach it more thoroughly. At the most thorough end of the spectrum, assessments in each of the areas should be discussed, then the combination of them. While that can be much work, it is less work than when such issues go unresolved for years.