Wikipedia:Comparison of Wikipedia's and Britannica's outlines of knowledge

Wikipedia's Portal:Contents features outlines, accessible from Portal:Contents/Outline of knowledge.

This page examines the differences between Wikipedia's Outline of knowledge and The Encyclopaedia Britannica's Outline of Knowledge (presented in its volume called the Propaedia).

Differences
Britannica's Outline of Knowledge is presented as a single continuous document (with suggested reading lists interspersed throughout). Wikipedia's Outline of knowledge is divided into standalone outline articles.

The Propaedia is printed in book form, forcing the reader to look up articles on the listed topics manually. Wikipedia's Outline of knowledge is linkified hypertext, letting the reader jump directly to an article on a desired topic simply by clicking on the topic. (There is a version of Britannica that was made available on CD in the mid 1990s, including the Propaedia, but it is somewhat out of date now, and getting more so.)

Britannica's Outline of Knowledge was created for the 15th edition of the Encyclopaedia Britannica, prior to the rest of the encyclopedia, as a plan from which to base topic coverage on – to shape it before it was built. It served initially to ensure quality, and once the encyclopedia was completed, as a topical guide. Wikipedia's Outline of knowledge is for the most part a reverse outline, built by gathering topics already appearing in Wikipedia and expanded from there, serving as an ongoing tool for identifying and solving problems such as gaps in coverage, naming inconsistencies, etc. – to shape the encyclopedia after-the-fact. It too serves as a topical guide, and due to its redlinks it also serves as a dynamic plan for further article creation. (Outlines are very versatile).

The Propaedia presents outline entries and article suggestions separately, presenting the names of Britannica's related articles at the end of each section of the outline. Wikipedia's Outline of knowledge functions as both an outline and directly as a table of contents, with article links embedded directly into the outline as topics.

The Propaedia includes 15 images (the plates on human anatomy), and the reader cannot add any. Wikipedia's Outline of knowledge includes many images (including maps, pictures, etc.), and supports the inclusion of images throughout.

Britannica's Outline of Knowledge is currently broader (covering the overall spectrum of subjects more evenly) and it is more refined. The original took a large team 8 years to complete, and has 517 pages (including suggested reading lists, which aren't part of the subject classification outline itself). Wikipedia's Outline of knowledge has been under development as part of the encyclopedia proper (in article space) since 2005, with the bulk of the development being done by a small team of contributors, and so far it has grown to about 500 pages (as of April 2009). Wikipedia's outline goes into more depth on some subjects, but has many blatant gaps Britannica's does not have.

Britannica's outline goes 7 levels deep. (As of May 2009) Wikipedia's Outline of knowledge goes 9 levels deep in some places, the hierarchy extending from page-to-page (when an outline page is the subtopic of another outline page), with even deeper coverage likely in the future.

The Britannica's outline uses outline numbering, Wikipedia's does not (except in outline pages' auto-generated tables of contents – these are displayed in the decimal outline format, and only show those topics/branches that are presented as headings). As manual numbering is infeasible and renders the auto-generated TOC unreadable, a new software feature would be needed to enable automatic outline numbering in Wikipedia.

Wikipedia's Outline of knowledge is growing and improving rapidly. We won't know how Britannica's is doing until its next revision.