Main Page | Recent changes | Edit this page | Page history

Printable version | #REDIRECT [[Thelemapedia:Disclaimers]]

Not logged in
Log in | Help


From Thelemapedia

This page will serve as a central operating point for the different categorization projects. For a quick introduction to categories, see Wikipedia:Category.

Table of contents

When to use categories

Categories should be on major topics that are likely to be useful to someone reading the article.

Article: Aleister Crowley
Useful category: Category:Occultists
Not useful: Category:Magicians whose name starts with A

Questions to ask to know if a category is the appropriate tool:

If the answer to either of these questions is no, then a category is probably inappropriate.

An article will often be in several categories. Restraint should be used, however — categories become less effective the more there are on a given article.

An article should not be in both a category and its subcategory, e.g. Aleister Crowley is in Category:Occultists, so should not also be in Category:Thelemic Occultists. Note: An exception would be an article that defines a category, and so is itself a parent article of subtopics as well as one in a series of like topics - for instance, placing Ohio in both Category:Political divisions of the United States and Category:Ohio. Another example would be cities for which there are categories: New York City belongs in both Category:Cities in New York and in Category:New York City.

Categories appear without annotations, so be careful of NPOV when creating or filling categories. Unless it is self-evident and uncontroversial that something belongs in a category, it should not be put into a category.

Exceptions to the above rules are categories such as Stub categories which are intended to aid the function of Wikipedia editing.

For alternative methods of grouping articles, and the circumstances in which they should be used, see Wikipedia:Categories, lists, and series boxes.

Categories applied to articles on people

A separate wikipedia page Wikipedia:Categorization of people was created where some finer points of when and how to apply categories to articles regarding people are in the process of being clarified.

Categories form a graph, not a tree

The software feature does not force a strict hierarchy or tree of categories, but allows multiple categorization schemes to co-exist simultaneously. Because each article can appear in more than one category, and each category can appear in more than one parent category, the categories do not form a tree structure, but a more general directed graph. It is even possible to construct loops in the category graph, but this is seldom a good idea.

Nevertheless, parts of the category graph will be tree-like, and it may be convenient to think of parts of the category graph as being like multiple overlapping trees.

Guidelines for assignment

How to create categories

Creating a category is as simple as adding a soft link to the appropriate article in the Category: namespace; for instance, to add Felis silvestris catus to the "fluffy creatures" category, you would edit the article and enter [[Category:Fluffy creatures]] at the bottom, but before interlanguage links. Although the link will not appear in the article text, a page called Category:Fluffy creatures is automatically created and it will list alphabetically all articles that contain the [[Category:Fluffy creatures]] link. The appeal of categories is that unlike lists, they update themselves automatically, and that one can use them to quickly find related articles. However, categories are not a substitute for lists, and you will find that many articles belong to both lists and categories.

Creating subcategories

Create subcategory pages by putting the name of the parent category on a category page that you would like to be the subcategory. Child categories (subcategories) are created by putting [[category:parent_category_name]] on the lower-level category pages. For example, on a (sub)category page called category:Roses you put [[category:Flowers]], Roses becomes a subcategory of Flowers.

When adding an article to a category, or creating categories, one should be careful to use the correct categories and subcategories. Horizontal categorization, directly below, refers to placing an article in the correct category while vertical categorization refers to placing an article in the correct subcategory.

When assigning an article into categories, try to be thorough in a "horizontal" sense. The topic may be associated with a geographic area, a historical period, an academic subfield, a certain type of thing (like a food or an ornament), and/or a special interest topic (like Roman Empire or LBGT). You might need to poke around the category hierarchy a bit to find the right place. Try searching for articles similar to the article you are categorizing to get ideas or to find the most appropriate place. (for instance, '1990' is more correctly in 'Category:Time periods' rather than 'Category:Places')

In the "vertical" dimension, you should probably be more frugal. A good general rule is that articles should be placed in the most specific categories they reasonably fit in. For example, Queen Elizabeth should not be listed directly under People, but Queens of England might be a good place for her. We know that all Queens of England qualify as Famous Britons and as Royalty, and all of those folks qualify as People. But sometimes there's a good reason to assign an article to two categories, one of which is a direct or indirect subcategory of another. For a well-argued case study, see John Lennon. ('1990' is actually more correct in 'Category:Years', a subcategory of 'Category:Time periods')

Whatever categories you add, make sure they do not implicitly violate the neutral point of view policy. If the nature of something is in dispute (like whether or not it's fictional or scientific or whatever), you may want to avoid labelling it or mark the categorization as disputed. Most categorizations are pretty straightforward, though.

Making groups of subcategories

When a given category gets too crowded, consider making several subcategories. Group similar articles together in a meaningful way that will hopefully be easy for readers to navigate later. Remember that several sub-categorization schemes can coexist (for example, if Category:Software gets too big, you don't have to choose between subdividing it by function or subdividing it by platform, you can simultaneously subdivide it in both ways).

A set of related categories often forms a hierarchy or a nexus. This can take several different forms, all of which are welcome and encouraged:

Category membership and creation

When writing the description for a category, give it a parent category. In fact, you should try to give it at least two parent categories. For example, Category:British writers should be in both Category:Writers by nationality and Category:British people. A few categories do only merely subdivide their parent category, but unless the parent category has many potential articles under it, or many potential subdivisions, if you can't think of a second parent category, it might be a better idea to fold your smaller category into the parent.

Wikipedia namespace

Categories relating to the Wikipedia namespace should be added only to the talk page of articles. For example, tags suggesting the article is needs work, or is listed on VfD would be placed on the talk page as they are relevant to editors, not an aid to browsing in the way ordinary categories are. Please use {{wpcat}} on the Category description page to show that it is a Wikipedia-namespace category.

General naming conventions

Special conventions for lists

Note that there are a growing number of instances where both the singular category (listing topics relating to) and plural category (listing instances of) exist, for example, Category:Opera and Category:Operas. Be careful to choose the right one when categorizing articles.

Categories requirements and usage

User browsing

Categories (along with other features, like cross-references) should help users find the information they are looking for as quickly as possible, even if they don't know that it exists or what it's called.

Links to categories

You can create a link to a category page without adding the page to that category by using a colon before the word Category. Example: [[:Category:Automotive technologies]] appears as Category:Automotive technologies.

Redirected categories

Although it is possible to attempt to redirect categories by adding a line such as #REDIRECT [[Category:Automotive technologies]] to a category, it is not generally recommended because of limitations in the mediawiki software. Categories "redirected" in this way:

  1. will appear as a subcategory of the target category.
  2. do not prevent the addition of articles to the redirected category. Articles added to the "redirected" category do not show up as in the target category.

Until these issues are addressed (in future versions of the software), #REDIRECT should not be added to category pages.

Category sorting

Contrary to some expectations, text after a pipe ("|") in a category link is not used in place of the category text. Rather, this text is used as the sort key on the category page itself. However, again contrary to expectations, that sort text is not displayed.

For example, the Category:U.S. Interstate Highway system uses this property to sort secondary interstates by their primary. That is, the category link in the article for Interstate 190 is [[Category:U.S. Interstate Highway system|90-1]]. This causes "Interstate 190" to be listed right after "Interstate 90" and right before "Interstate 290" under the heading "9" in the category page.

This feature is very useful for categories in which:

Using this method to sort category entries is sometimes informally referred to as the pipe trick. However, this use of the pipe character is very different from the original Wikimedia pipe trick which allows one to easily hide parenthetical disambiguation in links.

It is possible to force an article or subcategory to the top of the list by using a non-alphanumeric character as the first after the pipe. For example, using [[Category:Ford| Ford Motor Company]] (note the space) or [[Category:Ford|*Ford Motor Company]] would force that article to be displayed before all the others. However, note that this practice is controversial.

Retrieved from ""

This page has been accessed 2186 times. This page was last modified 06:47, 16 Jan 2005. Content is available under GNU Free Documentation License 1.2.

[Main Page]
Main Page
Recent changes
Random page
Current events

Edit this page
Discuss this page
Page history
What links here
Related changes

Special pages
Bug reports