Draft:Categorization

This page contains guidance on the proper use of the categorization function in BattleTechWiki. The central goal of the category system is to provide navigational links to pages in BattleTechWiki within a hierarchy of categories. Using essential, defining characteristics of a topic, readers can browse and quickly find sets of pages on topics that are defined by those characteristics.

Naming conventions[edit]

When naming a category, one should be particularly careful and choose its name accurately. Moving non-conventionally categorized pages to another category name (see {{Category redirect}}) imposes an additional overhead – an edit for each article and subcategory. Also, try to avoid names that are too long or too short. Short, straight-forward names, are preferred for categories, though it may be necessary at times to deviate from this principle for clarity or disambiguation.

Creating category pages[edit]

Before creating a new category[edit]

Categories are not the only means of enabling users to browse sets of related pages. And categories have several disadvantages, including:

  • Categories by default list only the name of a page. Individual category members cannot be annotated with descriptions or comments, so they give no context or elaboration for any specific entry. However, short descriptions can be displayed as annotations to the links displayed on a category page.
  • There is no provision for referencing any specific entry, to verify a topic meets a category's criteria of inclusion.

So, consider whether a list would be more appropriate for such a grouping of pages. Lists would also be more useful where it is important to see dates, for example, a list of Nobel laureates. And can provide options for sorting the entries.

Also, consider whether the category might be considered category clutter. Please see BattleTechWiki:Overcategorization, for more information on this.

Choosing a name for the category[edit]

A good category name is neutral, and as much as possible, defines the category inclusion criteria in the name itself.

Important: When choosing a name for the category, please be sure a similar category does not exist.

For example: You might want to add a sub-category for people to Category:Mexicans. Before creating that category, try to find it under a similar name. By starting at Category:People by nationality, you will discover that Mexicans are placed in Category:Mexican people.

Note: #Eponymous categories (categories whose name and topic is the same as an article, such as a category named after a person) should only be created if sufficient directly-related articles exist.

Creating the category[edit]

After you have determined an appropriate category name for the category, next try to find a suitable place for the new category. (For example, categories of people should be in the tree of "people" categories.) Please see #Category tree organization for more information on this.

Once you have determined where to categorize this new category, you should be ready to create the new category. To create a category,

  1. Add a page to the intended category. Do this by editing that page:
    1. At the bottom, add the name of the new category, (e.g.: [[Category:New category name]] )
    2. Save your edit. The as-yet-undefined category name will now appear as a red link in the category list at the bottom of the page.
  2. Next, click on that red link, which brings you to the new category page to create.
  3. Finally, at the bottom of the page, simply add the parent category (e.g.: [[Category:Parent category name]] ), which should usually be a hypernym of the sub-category. This will add the new category into the appropriate parent category.

Template:N.b. If something goes wrong, double check to see if you followed the steps properly and check if the wikitext is correct. For example, if the category fails to list in the parent category, the wikitext should be [[Category:Parent category name]], not [[:Category:Parent category name]].

Category description[edit]

Sometimes, a common-sense guess based on the title of the category isn't enough to figure out whether a page should be listed in the category. So, rather than leave the text of a category page empty (containing only parent category declarations), adding a main article which describes the topic, can help with that.

However, only linking to a BattleTechWiki article explaining the title is often not sufficient as a description for a category. It can be helpful – to both readers and editors – to include a clear description of the category, indicating what pages it should contain, how they should be subcategorized, and so on, and linking to one or more pages as background information.

In such cases, the desired contents of the category should be described on the category page, similar to how the list selection criteria are described in a stand-alone list. The category description should make direct statements about the criteria by which pages should be selected for inclusion in (or exclusion from) the category. This description, not the category's name, defines the proper content of the category. Do not leave future editors to guess about what or who should be included from the title of the category. Even if the selection criteria might seem obvious to you, an explicit standard is helpful to others, especially if they are less familiar with the subject.

The description can also contain links to other BattleTechWiki pages, in particular to other related categories which do not appear directly as subcategories or parent categories, and to relevant categories at sister projects, such as Commons. Another technique that can be used is described at BattleTechWiki:Classification. Like disambiguation pages, category pages should not contain either citations to reliable sources or external links.

Various templates have been developed to make it easier to produce category descriptions; see Category namespace templates. There are hatnote templates including {{Cat main}} and {{Category see also}}; others are listed at BattleTechWiki:Hatnote#Categories.

Additional considerations[edit]

Categories may have hundreds of members, displayed over many pages, with, at most, only 200 category entries on a single category page. To make navigating large categories easier, a table of contents can be used on the category page. The following templates are some of the ways of doing this:

  • {{Category TOC}} – adds a complete table of contents (Top, 0–9, A–Z)
  • {{Large category TOC}} – adds a complete table of contents with five subdivisions for each letter (Aa Ae Aj Ao At)
  • Consider using {{CatAutoTOC}} which uses the appropriate TOC for the number of pages on a category page.

Likewise, a maximum of 200 subcategories are displayed at a time, so some subcategories may not be immediately visible. To display all subcategories at once, add a category tree to the text of the category page, as described at Help:Category § Displaying category trees and page counts.

Category pages can have interlanguage links in the "Languages" list in the left sidebar (in the default skin), linking to corresponding categories in other language BattleTechWikis. To edit these on Wikidata, click on the "Edit links" link at the end of the languages list.

Categorizing pages[edit]

File:Category explanation.ogv

Every BattleTechWiki page should belong to at least one category, except for talk pages, redirects, and user pages, which may optionally be placed in categories where appropriate. Each categorized page should be placed in all of the most specific categories to which it logically belongs. This means that if a page belongs to a subcategory of C (or a subcategory of a subcategory of C, and so on) then it is not normally placed directly into C. For exceptions to this rule, see § Eponymous categories and § Non-diffusing subcategories below.

While it should typically be clear from the name of an existing category which pages it should contain, the text of the category page may sometimes provide additional information on potential category contents. One way to determine if suitable categories already exist for a particular page is to check the categories of pages concerning similar or related topics. Another way is to search existing category names as described here (top of page).

Since all categories form part of a tree-like hierarchy, do not add categories to pages as if they are tags.

Articles[edit]

Apart from certain exceptions (i.e. eponymous categories and non-diffusing subcategories – see below), an article should be categorised under the most specific branch in the category tree possible, without duplication in parent categories above it. In other words, articles should rarely be placed in both a given category and any of its sub- or parent (super-) categories. For example, the article "Paris" need only be placed in Category:Cities in France, not also in Category:Populated places in France. Because the first category (cities) is in the second category (populated places), readers are already given the information that Paris is a populated place in France by it being a city in France.

Categorization of articles must be verifiable. It should be clear from verifiable information in the article why it was placed in each of its categories. Use the {{Unreferenced category}} template if you find an article in a category that is not shown by sources to be appropriate or if the article gives no clear indication for inclusion in a category.

Categorization must also maintain a neutral point of view. Categorizations appear on article pages without annotations or referencing to justify or explain their addition; editors should be conscious of the need to maintain a neutral point of view when creating categories or adding them to articles. Categorizations should generally be uncontroversial; if the category's topic is likely to spark controversy, then a list article (which can be annotated and referenced) is probably more appropriate. For example, a politician (not convicted of any crime) should not be added to a category of notable criminals.

The defining characteristics of an article's topic are central to categorizing the article. A defining characteristic is one that reliable sources commonly and consistently refer to[1] in describing the topic, such as the nationality of a person or the geographic location of a place.

For example, Italian and artist are defining characteristics of Caravaggio, and so of the article on him, because virtually all reliable sources on the topic mention them.

Particular considerations for categorizing articles:

  • By convention, category declarations are placed at the end of the wikitext, but before any stub templates, which transclude their own categories.
  • Eponymous categories should appear first. Beyond that, the order in which categories are placed on a page is not governed by any single rule (for example, it does not need to be alphabetical, although partially alphabetical ordering can sometimes be helpful). Normally the most essential, significant categories appear first.
  • An article should never be left with a non-existent (redlinked) category on it. Either the category should be created, or else the link should be removed or changed to a category that does exist.
  • Categorization should not be made by the type of an article. A biographical article about a specific person, for example, does not belong in Category:Biography (genre).
  • Articles on fictional subjects should not be categorized in a manner that confuses them with real subjects. {{Category see also}} is useful for interlinking examples of real-world and fictional phenomena.

Eponymous categories[edit]

A category that covers exactly the same topic as an article is known as the eponymous category for that article (e.g. New York City and Category:New York City; Mekong and Category:Mekong River; Abraham Lincoln and Category:Abraham Lincoln).

Eponymous categories should not be created unless enough directly-related articles or sub-categories exist. However, this should not be done simply to reduce the number of categories displayed in an article.

An eponymous category should have only the categories of its article that are relevant to the category's content. For example:

Individual works by a person should not be included in an eponymous category but should instead be in a sub-category such as Category:Novels by Agatha Christie.

Articles with eponymous categories[edit]
  • The article itself should be a member of the eponymous category and should be sorted with a space to appear at the start of the listing (see § Sort keys below).
  • The article should be listed as the main article of the category using the {{cat main}} template.
  • Articles with an eponymous category may be categorized in the broader categories that would be present if there were no eponymous category (e.g. the article France appears in both Category:France and Category:Countries in Europe, even though the latter category is the parent of the former category). Editors should decide by consensus which solution makes most sense for a category tree. There are three options:
  1. Keep both the eponymous category and the main article in the parent category. This is used in Category:Countries in Europe to allow that region's country articles to be navigated together.
  2. Keep just the child article. This is used in Category:British Islands, to prevent a loop.
  3. Keep just the eponymous category. This is used for Category:Farmers in Category:People by occupation. Such "X by Y" categories sometimes cover a limited navigational set, not a topic (see § Category tree organization below), thus there is no logical article content.

If eponymous categories are categorized separately from their articles, it will be helpful to make links between the category page containing the articles and the category page containing the eponymous categories. The template {{Related category}} can be used for this. An example of this set-up is the linked categories Category:American politicians and Category:BattleTechWiki categories named after American politicians.

Files[edit]

Category tags should be added to file pages of files that have been uploaded to BattleTechWiki. When categorized, files are not included in the count of articles in the category, but are displayed in a separate section with a thumbnail and the name for each. A category can mix articles and images, or a separate file/image category can be created. A file category is typically a subcategory of the general category about the same subject, and a subcategory of the wider category for files, Category:BattleTechWiki files. To categorize a new file when uploading, simply add the category tag to the upload summary.

Freely licensed files should be uploaded to, and categorized on, Wikimedia Commons, instead of uploading and categorizing on BattleTechWiki. Existing freely licensed files should usually be moved from BattleTechWiki to Commons, with a mirror page automatically remaining on BattleTechWiki. (For an example of one such mirror page, see here.) Categories should not be added to these BattleTechWiki mirror pages, because doing so creates a new BattleTechWiki page that is subject to speedy deletion. Exceptions to this principle are made for mirror pages of images that are nominated as featured pictures and for those that appear on the BattleTechWiki Main Page in the Did You Know? column.

Images that are used in BattleTechWiki that are non-free or fair use should not appear as thumbnail images in categories. To prevent the thumbnail preview of images from appearing in a category, __NOGALLERY__ should be added to the text of the category. In such cases, the file will still appear in the category, but the actual image preview will not.

BattleTechWiki administrative categories[edit]

A distinction is made between two types of categories:

  • Administrative categories, intended for use by editors or by automated tools, based on features of the current state of articles, or used to categorize non-article pages.
  • Content categories, intended as part of the encyclopedia, to help readers find articles, based on features of the subjects of those articles.

Administrative categories include stub categories (generally produced by stub templates), maintenance categories (often produced by tag templates such as {{cleanup}} and {{fact}}, and used for maintenance projects), WikiProject and assessment categories, and categories of pages in non-article namespaces.

Article pages should be kept out of administrative categories if possible. For example, the templates that generate WikiProject and assessment categories should be placed on talk pages, not on the articles themselves. If it is unavoidable that an administration category appears on article pages (usually because it is generated by a maintenance tag that is placed on articles), then in most cases it should be made a hidden category, as described in § Hiding categories below.

There are separate administrative categories for different kinds of non-article pages, such as template categories, disambiguation page categories, project page categories etc.

In maintenance categories and other administrative categories, pages may be included regardless of type. For example, in an error tracking category it makes sense to group templates separately, because addressing the errors there may require different skills compared to fixing an ordinary article. For sorting each namespace separately, see § Sort keys below.

User pages[edit]

User pages are not articles, and thus do not belong in content categories such as Living people or Biologists. They can however be placed in user categories – subcategories of Category:BattleTechWikins, such as Category:BattleTechWikin biologists – which assist collaboration between users.

Similarly, user subpages that are draft versions of articles should be kept out of content categories, but are permitted in non-content or project categories, like Category:User essays. If you copy an article from mainspace to userspace and it already contains categories, wrap them inside {{Draft categories}}, remove them, or comment them out. Restore the categories when you move the draft back into article space. Two scripts are available to help with these tasks: User:DannyS712/Draft no cat and User:DannyS712/Draft re cat.

Also, do not transclude articles into your user pages: this will result in the user page being included in all the article's categories.

At Database reports/Polluted categories, a list of affected categories is maintained.

Draft pages[edit]

Drafts, no matter whether in the draft namespace or your userspace, are not articles, and thus do not belong in content categories. If you copy an article from mainspace to draftspace or your userspace and it already contains categories, then disable those categories. This can be done either by inserting a colon character to link to each category (e.g. change [[Category:Biologists]] to [[:Category:Biologists]]), or by wrapping them in {{Draft categories}} (e.g.{{draft categories|1=[[Category:Living people]] [[Category:Biologists]]}} etc.). After you move the draft into article space, remove the leading colons to re-enable the categories. If using the draft categories template, the categories will automatically work as normal in mainspace, but the template should be removed. The same system may be used in a new draft to list the categories it may have when moved to mainspace.

Drafts may be placed in the appropriate subcategories of Category:Drafts.

Template categorization[edit]

Templates are not articles, and thus do not belong in content categories. It is however a recommendation to place them in template categories – subcategories of Category:Templates – to assist when looking for templates of a certain type.

It is usually desirable that pages using a template are not placed in the same categories as the template itself. To avoid this, the category for the template should be placed on the template's documentation page, normally within a <includeonly>{{Sandbox other|...}}</includeonly> block; if there is no documentation page, the category for the template may be placed on the template itself, within a <noinclude>...</noinclude> block. When a <noinclude>...</noinclude> block is the last item in the template code, there should be no spaces or new lines between the last part of the template proper and the opening <noinclude> tag.

Categorization using templates[edit]

Many templates include category declarations in their transcludable text, for the purpose of placing the pages containing those templates into specific categories. This technique is very commonly used for populating certain kinds of administration categories, including stub categories and maintenance categories.

However, it is recommended that articles not be placed in ordinary content categories using templates in this way. There are many reasons for this: editors cannot see the category in the wikitext; removing or restructuring the category is made more difficult (partly because automated processes will not work); inappropriate articles and non-article pages may get added to the category.

When templates are used to populate administration categories, ensure that the code cannot generate nonsensical or non-existent categories, particularly when the category name depends on a parameter. Also, see Category suppression for ways of keeping inappropriate pages out of template-generated categories.

Category declarations in templates often use {{PAGENAME}} as the sort key, because this overrides any DEFAULTSORT defined on the page.

Hiding categories[edit]

In cases where, for technical reasons, administration categories appear directly on articles rather than talk pages, they should be made into hidden categories, so that they are not displayed to readers. This rule does not apply to stub categories or "uncategorized article" categories – these types are not hidden.

To hide a category, add the template {{BattleTechWiki category|hidden=yes}} to the category page (the template uses the magic word __HIDDENCAT__). This also places the page in Category:Hidden categories.

A logged-in user may elect to view all hidden categories, by checking "Show hidden categories" on the "Appearance" tab of Preferences. Notice that "hidden" parent categories are never in fact hidden on category pages (although they are listed separately).

Hidden categories are listed at the bottom when previewing. All users of the desktop version can see hidden categories for a page by clicking "Page information" under "Tools" in the left pane, or by editing the whole page with the source editor.

Redirected categories[edit]

Do not create inter-category redirects. See BattleTechWiki:Redirect § Category redirects for the technical details.

Category tree organization[edit]

Partial view of Wikipedia's category system from 2007. Arrows point from category to sub-category.

Categories are organized as overlapping "trees", formed by creating links between inter-related categories (in mathematics or computer science this structure is called a partially ordered set). Any category may contain (or "branch into") subcategories, and it is possible for a category to be a subcategory of more than one "parent" category. (A is said to be a parent category of B when B is a subcategory of A.) [2]

There is one top-level category, Category:Contents. All other categories are found below this. Hence every category apart from this top one must be a subcategory of at least one other category.

There are two main kinds of category:

Subcategorization[edit]

A tree structure showing the possible hierarchical organization of an encyclopedia
Items may belong to more than one category, but normally not to a category and its parent (there are, however, exceptions to this rule, such as non-diffusing categories). An item may belong to several subcategories of a parent category (as pictured).

If logical membership of one category implies logical membership of a second (an is-a relationship), then the first category should be made a subcategory (directly or indirectly) of the second. For example, Category:Federated Suns Commands is a subcategory of Military Commands, which in turn is a subcategory of BattleTech Universe.

Many subcategories have two or more parent categories. For example, Category:Federated Suns Commands should be in both Category:Military Commands and Category:Federated Suns Related Categories. When making one category a subcategory of another, ensure that the members of the subcategory really can be expected (with possibly a few exceptions) to belong to the parent also. Category chains formed by parent–child relationships should never form closed loops;[3] that is, no category should be contained as a subcategory of one of its own subcategories.[4] If two categories are closely related but are not in a subset relation, then links between them can be included in the text of the category pages.

Except for non-diffusing subcategories (see below), pages for sub-categories should be categorised under the most specific parent categories possible.

Sometimes proper subcategorization requires the creation of new categories.

Note also that as stub templates are for maintenance purposes, not user browsing (see § BattleTechWiki administrative categories above), they do not count as categorization for the purposes of BattleTechWiki's categorization policies. An article which has a "stubs" category on it must still be filed in the most appropriate content categories, even if one of them is a direct parent of the stubs category in question.

Diffusing large categories[edit]

Although there is no limit on the size of categories, a large category will often be broken down ("diffused") into smaller, more specific subcategories.

A category may be diffused using several coexisting schemes:

It is possible for a category to be only partially diffused—some members are placed in subcategories, while others remain in the main category.

Information about how a category is diffused may be given on the category page. Categories which are intended to be fully broken down into subcategories can be marked with the {{category diffuse}} template, which indicates that any pages which editors might add to the main category should be moved to the appropriate subcategories when sufficient information is available. (If the proper subcategory for an article does not exist yet, either create the subcategory or leave the article in the parent category for the time being.)

To suggest that a category is so large that it ought to be diffused into subcategories, you can add the {{overpopulated category}} template to the category page.

Non-diffusing subcategories[edit]

Not all subcategories serve the "diffusion" function described above; some are simply subsets which have some special characteristic of interest. They provide an exception to the general rule that pages are not placed in both a category and its subcategory: there is no need to take pages out of the parent category purely because of their membership of a non-diffusing subcategory. (Of course, if the pages also belong to other subcategories that do cause diffusion, then they will not appear in the parent category directly.)

Non-diffusing subcategories should be identified with a template on the category page:

  • The {{Non-diffusing subcategory}} templates should be used for sub-categories that are non-diffusing.
  • The {{All included}} can be used for categories where all child articles of a certain type are in the parent.

Note that some categories can be non-diffusing on some parents, and diffusing on others.

Category cleanup templates[edit]

  • Article with insufficient categories
    • {{Improve categories}} template indicates that the article needs additional or more specific categories. It is recommended that this template be placed at the bottom of the page, where readers will look for the categories.
  • Article with too many categories
    • Use {{Recategorize}} template when there are too many categories. Put this template on the top of articles.
  • Category unknown
    • If you're not sure where to categorize a particular page, add the {{uncategorized}} template to it, and other editors will help find appropriate categories for it.

Inappropriate categorization[edit]

Anyone may edit an article and remove a questionable categorization. If an article has an "incorrect" or "inappropriate" category, remove that category from the article, and replace it (if applicable) with a more correct category.

Even if an article may occupy the grey areas of a category's inclusion criteria, that is not a valid reason to keep the article in a category. If a particular article does not fit the inclusion criteria of a category, then the article simply should not be added to it.

If categorization of any particular page is disputed, please discuss the categorization on the talk page of the page in question. If the category seems reasonable, but questionable in some cases, consider whether you can solve (part of) the problem by writing a clearer #Category description.

See also[edit]

For browsing[edit]

For maintenance[edit]

Notes[edit]

  1. in declarative statements, rather than table or list form
  2. Mathematically speaking, this means that the system approximates a directed acyclic graph.
  3. This condition can be formulated in terms of graph theory as follows: the directed graph that has the categories as vertices and the parent-child relationships as edges should be acyclic.
  4. There is an exception to this for maintenance purposes. For example, Category:Hidden categories is a direct subcategory of itself and of Category:Extended-confirmed-protected pages and Category:Container categories, each of which is a direct subcategory of Category:Hidden categories.