Wikipedia:Glossing sources

For translation glosses like chien 'dog', see MOS:SINGLE

Providing a "gloss" when citing a source is not required but can be good practice and can help collaboration over time. A gloss is a brief explanation that accompanies a text. A gloss accompanying a reference added to an article should briefly describe what the reference supports and to what extent.

Adding a gloss like this means that even as the text of an article changes over time, future editors can know what the reference supports and to what extent. This helps prevent sources from becoming associated with statements that they do not support.

How to gloss a reference

References can be glossed in many ways. For example:

Direct quote:	<ref>Mobberley, 2007: "The Moon's equatorial diameter is 3,476 km and the polar diameter is 3,470 km."</ref>
Reader-visible summary:	<ref>Mobberley (2007) gives the equatorial diameter of the moon as 3,476 km.</ref>
Editor-visible note:	<ref>Mobberley, 2007 <!-- describes the equatorial diameter of the moon - NB: doesn't give the distance from the moon to the earth! --></ref>

How you decide to gloss a reference can be decided by several factors. Some factors that may decide how you provide a gloss include:

• Keep it brief. The purpose of a gloss is to help other editors understand what the reference supports and to what extent. Keep the contents of the gloss focused on that purpose. In most cases, extended quotations are unnecessary and add unnecessary bloat to an article.
• Copyright issues. Be careful not to quote any single source too extensively, including across glosses. If a single source is used extensively in an article, use a note or summary as the gloss.
• Nature of the gloss. Some glosses may be of interest to readers, whereas others may contain notes directed solely at future editors.

Regardless of the type of gloss you use, keep the gloss focused on the statement the reference is being used to support and how it supports it. If giving a summary, be objective and to-the-point. If giving a quotation, limit the quote (using ellipses if necessary) to only what is necessary to demonstrate how the statement made in the article is supported by the reference.

It is important to remember also that in some cases it may not be necessary to provide a gloss.

Why provide a gloss?

Glosses help future editors to know exactly what a reference supports and to what extent. Because of the way that Wikipedia is written, it can be difficult for future editors to know what a reference added in the past relates to. Consequently, a reference can "drift" around an article or the statement it supports can gradually change in meaning. This means that over time a reference can come to be associated with statements that it does not support.

Example

The following hypothetical example demonstrates one way in which a reference can come to be associated with a statement it does not support. It also shows how adding a gloss can prevent this from happening. The left-hand side shows a statement and a reference without a gloss. The right-hand side shows the same statement and reference with a gloss. The example shows how the statement changes over time and how an unglossed reference can come to be associated with statements they do not support.

	Without a "gloss"	With a "gloss"
Editor A:	The diameter of the Moon is 3,476km at its equator.[1] 1 Mobberley, 2007.	The diameter of the Moon is 3,476km at its equator.[1] 1 Mobberley, 2007: "The Moon's equatorial diameter is 3,476 km and the polar diameter is 3,470 km."
	Both of these are correct and supported by the reference.
Editor B:	The Moon is 250,000km from the Earth. Its diameter is 3,476km at its equator.[1] 1 Mobberley, 2007.	The Moon is 250,000km from the Earth. Its diameter is 3,476km at its equator.[1] 1 Mobberley, 2007: "The Moon's equatorial diameter is 3,476 km and the polar diameter is 3,470 km."
	The new sentence about the distance from the Earth is incorrect. The second sentence is still correct and supported by the reference.
Editor C:	The Moon is 250,000km from the Earth and is 3,476km wide at its equator.[1] 1 Mobberley, 2007.	The Moon is 250,000km from the Earth and is 3,476km wide at its equator.[1] 1 Mobberley, 2007: "The Moon's equatorial diameter is 3,476 km and the polar diameter is 3,470 km."
	This edit combined the two sentences (for whatever reason). In the unglossed version, it is now unclear which part of (or to what extent) the sentence is supported by the reference.
Editor D:	The Moon is 250,000km from the Earth.[1] 1 Mobberley, 2007.	The Moon is 250,000km from the Earth.
	This edit removed the second part of the sentence (for whatever reason). The editor of the unglossed version didn't know that first part of the sentence was unsupported and so kept the reference in place.	This edit removed the second part of the sentence (for whatever reason). The editor of the glossed version knew that first part of the sentence was unsupported by the reference and so removed the reference.
Editor E:	The Moon is 250,000km from the Earth.[1] 1 Mobberley, 2007.	The Moon is 250,000km from the Earth.
	For the unglossed version, the statement about the distance of the moon from the Earth appears to be referenced properly. In fact, the reference does not support the sentence.	Future editors of the glossed version know that the statement about the distance of the Moon from the Earth is unsupported.

See also

• Wikipedia:Citing sources