The following system is used to assess the quality of a Wikipedia article. The system is based on a letter scheme that reflects principally how factually complete the article is, though language quality and layout are also factors.
The quality assessments are mainly performed by Wikipedia editors, who tag Talk pages of articles; some bots set the class tag for assessment based on other Talk tags or based on editor selected values. Editor assistance tools like Rater apply automated ORES or Lift Wing article assessments, offering a prediction based on structural characteristics of the page (e.g. sectioning and references) that correlate with quality, for the class tag. These tags are then collected by a bot, which generates output such as a log and statistics. For more information, see Using the bot. In 2023, project-independent quality assessments were introduced, so editors only have to rate an article once and it applies to all associated projects.
Most grades are assessed by individual editors according to the criteria on this page. Generally speaking, all editors, including editors who have written or improved an article, are encouraged to boldly set any quality rating that they believe is appropriate, except for the GA, FA, and A-class ratings. GAs (Good Articles) are generally reviewed by a single independent editor after a nomination at WP:Good article nominations. FAs (Featured Articles) are reviewed by several editors at WP:Featured article candidates. Be aware that a few projects have opted out of the standard quality scale, and use their own variation of the criteria more tuned for the subject area, such as Wikipedia:WikiProject Military history/Assessment.
It is vital that editors not take these assessments of their contributions personally. It is understood that we each have our own opinions of the priorities of the objective criteria for a perfect article. If there is disagreement over the quality rating of an article, then it should be discussed on the article's talk page.
As of August 2024, over eight million articles have been assessed. Several other languages are also using this assessment system or a derivative thereof.
Note: Some WikiProjects omit some of the standard classes, most often A-Class, especially when they lack an assessment team.
Some WikiProjects use other assessments for mainspace content that do not fit into the above scale:
See also Wikipedia:WikiProject Military history/Assessment which utilises a parallel scheme of "CL-Class", "BL-Class" and "AL-Class" for list articles.
Further grades are commonly used by WikiProjects to categorize relevant pages in other namespaces. The precise application of these grades may vary depending on their usage by individual WikiProjects.
Note that some WikiProjects deal exclusively with non-mainspace content and may use their own customised assessment schemes tailored to a specific purpose: see Wikipedia:WikiProject Portals/Assessment for one such example.
For an index of all WikiProject assessment pages, see Category:WikiProject assessments.
This clickable imagemap, using the article "Atom" as an example, demonstrates the typical profile for an article's development through the levels. Hold the mouse over a number to see key events, and click on a number to see that version of the article. Please note that until 2008, a C-Class rating did not exist on the project, and as such this grading is retroactive. Also, in 2006 references were much less used, and inline references were quite rare; a barely-B-Class article today would typically have many more references than this article did in late 2006.
There is a separate scale for rating articles for importance or priority, which is unrelated to the quality scale outlined here. Unlike the quality scale, the priority scale varies based on the project scope. See also the template {{importance scheme}}.
The WP 1.0 bot tracks assessment data (article quality and importance data for individual WikiProjects) assigned via talk page banners. If you would like to add a new WikiProject to the bot's list, please read the instructions at Wikipedia:Version 1.0 Editorial Team/Using the bot.
The global summary table below is computed by taking the highest quality and importance rating for each assessed article in the main namespace.
|class=B
in the banner. Again, the "FA" and "GA" labels should not be added to articles unless they are currently designated as such. Tools in the See also section can help with the assessment process.