Help:Understanding categories

Categories are used to organize the pages of a wiki. Help:Category describes how to add or remove a category. This page will help you understand what kinds of categories to add and how to organize them.

Regular pages versus category pages
When you add a category to a regular page, you are saying "this page is a part of this category". When you add a category to a category page, you are saying "everything in this category is also a part of this other category". This can cover more pages than you want and may not be correct in all cases. In general, it is safer to add a category to a regular page than it is to a category page.

For example, a Golden Retriever is a dog, and dogs are canines. If you were to put   on the Canines category page, you would be saying that all canines are dogs. This would not be correct because canines also include wolves, jackals and coyotes.

However, you could put   on the Dogs category page, because dogs are a type of canine.

On the page for a terrier, you would put   on it. You could also put   on its page, but it may be simpler to just use the Dogs category alone.

Choosing categories
When a wiki is getting started, categories can be chosen for the most-likely subjects and may wind up not having very many pages in them. After the wiki is established, users need to take care not to create categories unless they would actually be needed. In this case, being needed refers to how many pages will be in that category. After a few years, the members of a wiki should have a pretty good idea of what kinds of subjects, and therefore categories, a wiki will cover.

Using the Golden Retriever again as an example, if there were only one or two of them on a wiki, then having a "Golden Retrievers" category probably wouldn't be necessary and could instead by covered by the "Dogs" category.

Another factor that needs to be considered would be "is this category name too long or too specific?" You could have a "Golden Retrievers with red body fur and black leg fur" category. But unless there were a large number of pages about Golden Retrievers that have that specific fur pattern, it would not be necessary or could be better served with a more-general category like "Golden Retrievers with unusual fur" or even "Dogs with unusual fur".

Overly-descriptive category names
The longer a category name is, the more difficult it is to use. When typing the category, the wiki will automatically suggest existing ones that match what you've typed so far. If the auto-suggest doesn't work, displays several choices, or there are more choices than it can display, a person may have to type the category by hand. In these cases, spelling mistakes can lead to new categories being created by accident.

A category name like "Golden Retrievers with red face fur, fair body fur and black leg fur" is a lot for a person to type and takes up a lot of room at the bottom of the page when the categories are displayed. A shorter category name like "Golden Retrievers with unusual fur" would be better. A few more details about what the unusual fur is could be put on the category page itself.

An overly-descriptive category name may also be of interest to only one person or a small handful of people. When picking a name for a category, ask yourself, "Is this something that a lot of people are going to be interested in, or just me?" If the answer is "just me", you probably shouldn't add that category. Look for an existing category to use instead.

Long category page descriptions
When creating the page for a category, the information should be kept short as a general description of the category. In general, no more than one or two sentences.

Category pages should not be used to replace a regular page. If a category page has a lengthy discussion, then that information needs to be moved to a regular page. Remember, categories are used to organize a wiki.

Duplicate categories
If there are two categories that are saying pretty much the same thing, see if one of them could be used in place of the other. For example, if you had "Poodles with very pale brown fur" and "Poodles with beige fur", the beige category could be used instead because beige is that kind of color and it is a shorter category name.

Excessive categories
Too many categories present too many choices for people. If there are more than a dozen categories on a page, consider removing some or consolidating them into fewer categories. Categories that look like they are of the "only of interest to a few specific people" are good candidates for being replaced by general category.

On short and stub pages, avoid having more categories than actual content on the page. A lot of the time, what's in the categories could just as easily be put on the page itself, which helps fill it out.

On wiki that have Achievement Badges enabled, it is tempting to add a category just to earn a badge. This can lead to frivolous, overly-descriptive or even just plain incorrect categories being added. A category should not be added just to add a category and get a badge. It should be added when the category will help better organize the page and is a subject that other people would be interested in.

Maintenance
Administrators may want to review the list of categories at Special:Categories to see if there are any with only a few pages in them and determine if those categories could be consolidated together or replaced by a general-purpose category.