This essay is an attempt to put down some thoughts which could potentially lead to a Wikipedia Guideline on when comparison articles comply with the Wikipedia policy No Original Research.

Comparison articles are listed in Category:Comparisons and its subcategories. An example is the article Canadian and American politics compared. A similar article, Politics of Australia and Canada compared was nominated for deletion on 27 October here.

Wikipedia policy on No Original Research states, amongst other things:

Editors often make the mistake of thinking that if A is published by a reliable source, and B is published by a reliable source, then A and B can be joined together in an article to advance position C. However, this would be an example of a new synthesis of published material serving to advance a position, and as such it would constitute original research.

Although a comparison article does not necessarily explicitly advance a new position, it does nonetheless constitute a synthesis of ideas.

Where an article is written comparing A to B it is identifying differences between A and B. These differences constitute a synthesis of ideas, independent of either A or B.

If the only Reliable Sources cited are those which either confirm A in isolation or B in isolation, then the differences identified by the comparison article constitute a novel synthesis of ideas, and hence are Original Research.

If no sources can be found that make the comparison then it is likely that the article subject is not Notable.

Comparison articles should not be deleted, however, if they can show:

1. That a reliable source has made the said comparison. (e.g. Parties Long Estranged: Canada and Australia in the Twentieth Century)
2. That reliable sources could be readily found for the article.

1. If a comparison article does not contain a reference to reliable sources making the stated comparison, it should be tagged to give the article's editors time to find these sources. A discussion should also be started on the relevant talk page. A special template could be designed for these purposes (perhaps along the lines of {{Synthesis}}) and a user warning template could be designed for article creators.
2. If after a reasonable delay, no reliable sources have been provided, the article should be Nominated for Deletion and this (guideline) cited. It may be useful to merge some of the article into the articles on the subjects being compared (in the above case, Politics of Canada and/or Politics of the United States).
3. If reliable sources can be provided for some, but not all, of the comparisons made, then the other comparisons should be tagged with {{syn}}, and if not provided then the comparisons should be removed.