Wikipedia:Categories, lists, and navigation templates

Category workers, list builders and , and series box designers all endeavor to develop comprehensive networks of links for navigating the encyclopedia. Because of this, increasingly, multiple entries to fields of knowledge are being provided. Take "symphonies", for example:

It is neither improper nor uncommon to simultaneously have a category, a list, and a navigation template which all cover the same topic. These systems of organizing information are considered to be complementary, not inappropriately duplicative. Furthermore, arguing that a category duplicates a list (or vice versa) at a deletion discussion is not a valid reason for deletion and should be avoided.

Consider that lists may include features not available to categories, and building a rudimentary list of links is a useful step in improving a list. Deleting these rudimentary lists is a waste of these building blocks, and unnecessarily pressures list builders into providing a larger initial commitment of effort whenever they wish to create a new list, which may be felt as a disincentive. When deciding whether to create or avoid a list, the existence of a category on the same topic is irrelevant.

Below is a comparison of how these techniques group information and the advantages and disadvantages of each.

Compared with a list, a category may have both advantages and disadvantages.

Example of a category page. Every page in the article namespace should have at least one category. Categories should be on major topics that are likely to be useful to someone reading the article.

A category is probably inappropriate if the answer to the following questions is "no":

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 usually not be in both a category and its subcategory, e.g. Microsoft Office is in Category:Microsoft software, so should not also be in Category:Software—except when the article defines a category as well as being in a higher category, e.g. Ohio is in both Category:States of the United States and Category:Ohio (a good way to understand this exception is that if an article exists, and then a category is created on the same subject as the article, it should not cause the article to be removed from any of its categories).

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