Feminist SF Wiki:Categories and "by name" subcategories
In general people and things should be categorized directly within the relevant category. For instance, "screenwriters" would be categorized with category:Screenwriters. This produces an alphabetical listing in Screenwriters category, and combined with {{DEFAULTSORT:}Lastname, Firstname}}, effectively places people (or things or entities) in the alphabetical index.
However, for categories that are large (more than 200 items (files and/or categories)), a slightly amended rule should be considered, that better segregates different types of content.
In large categories, subcategories, indexes, lists, and other special pages are not easily found, especially if they are later in the alphabet and the reader has to go to the "next page" (and so on) to get to them. Pipe-sorting can fix this, but if it is accidentally left off, it is hard to catch the error. In these kinds of large categories, therefore, it is better to separate the types of content. In particular, the named entities may be placed in a subcategory by type of sorting (usually, "by name"), and the other related subcategories and articles, lists, indexes, etc., will be the only entities in the primary category.
For instance, category:Writers has many indexes, lists, and subcategories, as well as many actual "writers". So, the alphabetical index of writers (the people) may all be gathered in category:Writers by name; the category category:Writers then provides access to the variety of indexes, lists, and categories of writers, and the alphabetical index of writers is one click further. It is a good idea to prominently display the alphabetical index category on the category page itself.
Of course, one then wants to hierarchically organize the "by name" groupings, to create a "by name" tree -- for instance, category:People by name would include category:Writers by name which would include category:Women writers by name. Because there will be a relatively small number of these unique-content by-name categories, they should simply all be sorted with the pipe trick to be at the beginning of the subcategory list.