Wikipedia:Cascading content

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Visualization of the content inheritance model proposed in this essay.

Cascading content is a way to organize Wikipedia that minimizes duplicated content. Article sections that are essentially summaries or introductions to full articles are replaced by transclusions of the lead section of said articles.

The problem[edit]

Some articles have many sections that are essentially summaries or introductions to other articles. For example, the article Philosophy has a section on Metaphysics, Logic, Ethics, etc. These articles, in turn, have sections about more specific topics, such as Propositional logic, First-order logic, etc. which in turn may have sections about even more specific topics, such as Truth table or Tautology. The sections in the more general articles often contain information repeated in the introductions of the more specific articles, in some cases even copy-pasted (in one direction or the other). In other cases, the sections contain information that the main articles don't, or the other way around, because editors that work on the sections sometimes don't work on the main articles (or vice versa) and even if they did, it's not always easy to keep articles synchronized.

The solution[edit]

Using the template {{extract}} it's possible to transclude the lead section of any article. This allows to replace the text of the sections that have a main article, for the lead section of said main article. With this strategy, we gain several benefits:

  • Reduced maintenance – now we just need to improve the introduction the lead of which we're transcluding, and all the transcluding articles will improve with it.
  • More collaboration by leading all interested editors to edit the same article, so that they work together instead of in parallel.
  • Increased coherence of the encyclopedia by reducing contradictory and outdated information.
  • Better attribution of credit to the real authors of the content, by minimizing content copy-pasted without attribution.
  • Better quality of content, because before replacing a summary section with a transcluded lead section, it's necessary to merge the contents of both into the lead to be transcluded, thereby incorporating all valuable content into a single section.

The reason for the title "Cascading content" is because as this technique is applied in more and more related articles, a cascading pattern emerges. For example, the article Philosophy may pull material from Ethics which may pull material from Meta-ethics, and so on.

Sometimes we don't want to transclude an article's lead section of an article, but rather a body section of the article. For example, maybe we have an article with a section about the history of metaphysics and we want to transclude the History section of the article Metaphysics, rather than the lead section. For such cases, the template {{extract}} has a second parameter where we may specify the title of the section that we want to transclude, like so: {{Extract|Metaphysics|History}}

Technical considerations[edit]

Unwanted elements[edit]

Sometimes the article whose lead section we want to transclude is preceded by templates like {{other uses}} that are irrelevant in the transcluding section, or by infoboxes or images that for some reason or another, we don't want to transclude. In such cases, we can wrap the content that we do want to transclude with the tags <section begin=intro /> y <section end=intro /> and the template {{extract}} will transclude the content within the tags, rather than the full lead section.

Self links[edit]

When an article links to itself, the link is shown in bold rather than blue (for example this is a link to this very page). This feature of the software can become undesirable when we transclude a lead section that contains a link to the transcluding article. For example, the lead section of the article Ethics may contain a link to Philosophy, so if we transclude it, the link will be shown in bold. This problem can be avoided through redirects. For example, if the article Ethics links to Philosophic instead of Philosophy, the link will be shown blue, even if it redirects to Philosophy. This annoying issue may receive a technical fix in the future if this technique becomes widespread.


Sometimes a reference in the transcluded article has the same name as another reference in the transcluding article. This may cause a reference name conflict and error. To solve this, simply rename one of the references.

In other cases, the body of the reference may be in some other part of the transcluded article, and the lead section may only be citing it, in which case the transcluding article will show an "unknown reference" error. To solve this, simply move the body of the reference to the section to be transcluded. If the original article from which you are transcluding consistently uses list-defined references (all reference citations are collected at the bottom of the article), the reference material should be left where it is in that article, and a copy of the reference citation put into the references section of the transcluding article.

See also[edit]