Notability guidelines, whether categories which are considered inherently notable or something along the likes of WP:GNG, should be as consistent and simply defined as possible. Any such guideline which contains inadequately justified exceptions, provisos, and/or loopholes is an example of notabilitymandering (a portmanteau of "notability" and "gerrymandering").

Consider the following example:
All foo are inherently notable except for/provided that bar

Such statements can be acceptable at times, given that bar is a reasonable and non-arbitrary exception. But if bar is a single article, or a few articles, that is/are excluded from the category for such reasons as WP:IDON'TLIKEIT or WP:WHOCARES, or a proviso such as length or number of redlinks that is irrelevant to the article's content and/or relationship to the category it should be removed. (Practical considerations, such as the number of all foo potentially drowning out notable foo, may be permissible sole reasons for such an exception, but in that case the most reasonable bar ought to be chosen.)

This starts becoming more important if there are multiple such exceptions and provisos, or especially when they are nested. Consider:
All foo are inherently notable except for bar, but including article fizz within group bar

Such criteria should be avoided unless there is a really good reason for their inclusion.

Even though "inherent non-notability" doesn't exist on Wikipedia, any category of articles that is discouraged or prohibited (such as WP:NOT, or what the community has decided as not inherently notable) should also follow this principle. Consider the example

Foo is not an inherently notable category, but article foo1 within foo is inherently notable

Such criteria should be avoided without really good cause lest it become the analogous evil of nonnotabilitymandering.

Consider inherently notable category 1. Category 2, a subcategory of 1, is also inherently notable. However, category 3, a subcategory of 2, is not inherently notable, and neither is category 4, a subcategory of 3. Category 5, a subcategory of 4, should NOT be inherently notable without good cause.

Any chronological categories (such as lists of Heads of State, etc.) should not exclude inherent notability to any member based on chronology (e.g. the Grand Poobahs of Freedonia are inherently notable if and only if they served after 1978) without good cause. Especially discouraged are multiple such exclusions (e.g. the Grand Poobahs of Freedonia are inherently notable if and only if they served before 1953 or after 1978).

Exceptions to rules or decisions on notability are not notabilitymandering provided that they are legitimate and reasonable. Indeed, many of Wikipedia's actual notability guidelines are quite detailed. This even applies for nested exceptions or provisos, although the more arcane and counter-intuitive they are the bigger the onus is for justifying their existences. "Extraordinary exceptions require extraordinary justifications" is a good rule of thumb.

WP:NOTLEVEL applies across categories in the encyclopedia. This applies to individual groups of inherent notability. While this can be construed in spirit to try to make notability within a given topic or category an even playing field, it does not apply across topics like NOTLEVEL and in any case recognizes any legitimate iniquities in the playing field of notability for the given topic.

This user-submitted essay should not be used to trump such established policies as the general notability guideline or any of the other formalized notability guidelines. If you believe that any part of such guidelines is an example of notabilitymandering, please take such concerns to the appropriate channels and do not take them into your own hands and violate the guidelines.

Nor is this in conflict with WP:OTHERSTUFFEXISTS. That essentially states that article X having passed some sort of notability test and being similar to article Y does not necessarily imply that article Y will pass that test. This essay merely states that, in the absence of any inherent notability (which voids OTHERSTUFFEXISTS), the test between similar articles X and Y should be the same without good reason to the contrary, and also that any inherently notable category that includes one article should include the other without good reason to the contrary.

Finally, as WP:INHERENT says, even inherently notable articles are still subject to such core rules as verifiability, no original research, neutral point of view, and WP:BLP.

• WP:Notability, for notability in general
• WP:INHERENT, for inherent notability in general
• WP:GNG, any articles that pass this are immune from any discussion of notabilitymandering
• WP:NOTLEVEL, which is not necessarily notabilitymandering