TechInfoDepot:Categorizing redirects

This is a TechInfoDepot guideline for placing redirect pages into categories. It is intended to document current practice and suggest best practice in other areas and indicate where categorization of redirects can be misleading.

When to categorize a redirect
Most redirects should not be placed in article categories. There are, however, maintenance categories specifically for redirects, and most should be in one of those. There are some situations where placing a redirect in an article category is acceptable and can be helpful to users browsing through categories. The following are examples of some of these situations:

Categories just for redirects
There are a series of categories that are used only for redirects. Articles are placed in categories by templates. These categories explain why the redirect exists, for example R from merge means it was created by a merge or R from alternative name means that the redirect is an alternative name for the main title.

These categories are only intended to contain redirects, and are helpful in keeping track of redirects and further subcategorizing them as needed. They include both redirects within main namespace and in other namespaces. They are often applied using templates, though such categories can also be created and populated directly. This categorization is intended for TechInfoDepot editors, not readers. For a list of the templates used to populate such categories, see TechInfoDepot:Template messages/Redirect pages. The templates can also be found in Category:Redirect templates; the categories are subcategories of Category:TechInfoDepot redirects.

However, Category:TechInfoDepot redirects itself is not meant to contain any redirects, and Category:Redirects is purposely empty.

Redirects whose target title is incompatible with the category
Alternative names should not look out of place on a category page. This is often a way to satisfy disagreements over renaming an article when more than one name seems equally valid. The alternative name(s) becomes a redirect and gets categorized the same way as its target. Another example is when a single article covers things known by multiple names, such as a person who is known in multiple fields of endeavour under different names, a merged article about three different newspapers, or a sketch comedy television show whose name exists on TechInfoDepot as a redirect to the comedy troupe that created it. In such a case, consideration needs to be given to which title should be reflected in an individual category. Note that placing such a category on the target article, with the alternative title in pipetext, does not accomplish the desired purpose, as pipetext in a category link only affects how a title is ordered alphabetically, not how it actually appears.
 * Examples:
 * The comedy troupe The Vestibules had a radio show called Radio Free Vestibule. Although the article The Vestibules covers both topics and Radio Free Vestibule is a redirect, any radio show categories need to be on the redirect, rather than the main article, so that those category lists correctly display the actual title of the radio show.
 * 24 Heures is a French-language newspaper in Montreal, but is covered in the article on its English-language sister publications 24 Hours. However, the French-language newspaper and Montreal newspaper categories must be placed on the redirect, as 24 Hours is not the name of a French-language newspaper published in Montreal, while 24 Heures is. Those categories should contain the correct name of the Montreal publication.
 * Wile E. Coyote and Road Runner is an article that covers both the cartoon and its titular characters. Categories that refer to one of the characters, but not both—such as Category:Fictional coyotes and Category:Fictional birds—are placed on the appropriate redirects.

Alternative names for articles
The primary function of the category system is to allow readers to browse through articles. The category system is often used like an alphabetical index. It is sometimes helpful for redirects from common alternative names to appear in the index list. Editors should consider whether alternative names should be mixed in with other names, or not. Sometimes an entirely new category is more appropriate (see Categorization of multiple taxonomies below).
 * Examples:
 * Lift bridge redirects to Vertical lift bridge – both are in Category:Bridges

Subtopic categorization
Some subtopics of articles have well-known names and, over time, may expand to become separate articles. Many articles cover several topics that have been combined. This can happen following a merge of several related articles. Often there are redirects pointing to these subtopics. These redirects can be categorized. In some cases, the categories for the redirects that point to the subtopics will be different than the categories for the entire article.
 * Example of similar categorization:
 * Butterfly vertebrae points to a subsection of Congenital vertebral anomaly – both appear in Category:Dog health


 * Examples of different categorization:
 * Bibliography of J. R. R. Tolkien (appearing in Category:Bibliographies by writer) points to a subsection of J. R. R. Tolkien (appearing in several other categories).
 * Prohibition in Finland (appearing in Category:History of Finland, Category:Finnish society, Category:1932 in Finland, and Category:Prohibition by country) – redirects to a subsection of Prohibition (appearing in Category:Prohibition and Category:Alcohol law)

Categorization of multiple taxonomies
Some articles can be organized by more than one taxonomy. An example of this is the organization of animal and plant articles by common names and binomial name taxonomy. This is possible by categorizing the article one way and categorizing the redirect a different way. In this case, the alternative categorization of the redirect will not appear in the article unless it is manually added.
 * Examples:
 * Category:Genus Panthera provides a single alphabetical listing of articles and redirects using the binomial Linnaean classification and Category:Panthera contains articles using common names.
 * An example for plants is: Category:Banksia taxa by common name and Category:Banksia taxa by scientific name.

Categorization of list entries
Some well-organized lists have redirects pointing at their subsections. In such cases, categorization of the redirects can be an alternative way of browsing entries in a long list. It can also provide an alphabetical listing for lists that are not organised alphabetically, for example, lists organised in a chronological order. Redirects to sections of minor character lists should generally only be categorized within that fictional setting, and not in the wider fictional categories.
 * Examples:
 * Category:EastEnders characters provides a single alphabetical listing of both minor and major characters in the BBC soap-opera EastEnders. However, the minor character redirects should not be categorised outside the EastEnders category structure, e.g. not Category:Fictional characters by occupation.
 * Category:Middle-earth horses provides a single alphabetical listing of both named horses and named ponies in J. R. R. Tolkien's Middle-earth.

How to categorize a redirect
A redirect may be categorized in the same way as for any other article. For clarity, all category links should be added at the end of the page, after the redirect statement and any redirect templates.

The redirect will appear in the specified categories but formatted differently than articles (by default, in italics, see Technical Note below).

Example 1– a redirect to page xxyyzz, using the printworthy redirect template, and in categories aaa and bbb, would look like:
 * 1) REDIRECT xxyyzz

Example 2– a redirect to an article subsection with heading 'title' using a link anchor (see Anchor):
 * 1) REDIRECT xxyyzz

Example 3– a common redirect need: "ttuuvv" to a geology page xxyyzz, using the R to section redirect template to point to the article and section where the common term is defined, and which should be in categories aaa, bbb, ccc and ddd (the parent article may have a few more, eee, fff, etc.), all of which are the categories of the parent article. This example would look like this:
 * 1) REDIRECT xxyyzz


 * Notes:
 * The  must come first.   types can be placed on their own lines after the above. Redirect category (Rcat) templates, , etc., may be placed anywhere after the redirect. It is conventional to place them before categories, but it is no longer necessary (as it once was) to place them immediately on the same line as the redirect.
 * is a Magic word in wikimarkup language that fills in the pagename, one can retype "ttuuvv" (without the quotes) and give that as the first pass parameter to the template instead. This is in fact a pipetrick parameter for when the template builds a list of  entries for you. (see more below)
 * The categories parameters listed in the later part of the template can be captured off the target page "xxyyzz" when you check the link (regardless of whether it's a section linking redirect) and captured by drag and drop from the categories bar. The highlighted category names (capture with [CTRL]-[C] keys) will automatically be pasted in (using [CTRL]-[V] keys) with the pipe characters ('|') needed to separate the parameters. (or other computer type/browser equivalent keystroke combinations)
 * The first parameter represented by || above is in fact the pipetrick sorting parameter used to group pages, and for redirects, some TechInfoDepotns use the convention of prefixing the sort to "{" or (most often) "}" which look like: and  respectively. This is a compromise convention since the TechInfoDepot community has never had good consensus on "whether to" or "how to" categorize redirects, except as redirects in redirect categories. By using such prefixes, they always sort in a group at the very end of the category list.


 * General information note: ALL THE, templates, have as their sole purpose adding a redirect sub-category (see ) on the page to aid in maintenance. Generally speaking, one such template categorizes redirect pages to the sub-category, though it may be "aliased" using several alternative phrasings, themselves redirects of templates. (Common alias alternatives are: Other vs. alternative, capitalization vs. capitalisation and such spelling/phrasing variants like "R to singular" and "R from plural")

Technical note
The appearance of a redirect link on category pages and in search results is determined by the CSS class "redirect-in-category" and the specification for that class in MediaWiki:Common.css. By default, this class is set to "italics", although this may be changed by the user. In the past, no distinction was made for users, which fueled the controversies over how to categorize redirects. By displaying them in italics, redirects are easy to pick out. Perfectly good (and in many cases better known) terminology implemented as redirects for technical reasons can now be categorized for the readers to browse, and for editors to know and use as needed.