Wikipedia's content policies require inline citations for all direct quotations, for contentious material, whether negative, positive, or neutral, about living persons, and for any material that has been challenged, or is "likely" to be challenged.
Wikipedia's community uses the working definition for the word likely: "probable; having a greater-than-even chance of occurring" or "having a high probability of occurring." Many statements are likely to be challenged, and many statements are unlikely to be challenged.
- If, based on your experience, a given statement has a greater than 50% chance of being challenged in good faith, either by removal, in a discussion on the talk page, or by the addition of a  or similar tag, then you should supply an inline citation for that material. This will be the case, for example, every time you add a controversial fact to an article.
- If, based on your experience, a given statement has a less than 50% chance of being challenged, then inline citations are not required for that material.
- ^ "Likely". Merrian-Webster. Retrieved 5 September 2015.