In the context of Biographies of Living Persons (BLPs), what specific type of source, while generally acceptable, requires extra caution and scrutiny before being used to support potentially controversial claims?

In the context of Biographies of Living Persons (BLPs), self-published sources, including sources published by the subject themselves or their close associates, require extra caution and scrutiny before being used to support potentially controversial claims, even though they might be generally acceptable for certain limited purposes. Self-published sources are materials where the author is also the publisher, meaning there is no independent editorial oversight or fact-checking process. While Wikipedia generally prefers independent, third-party sources, self-published sources can sometimes be used to support uncontroversial information about the subject, such as their date of birth or official website. However, when dealing with potentially libelous, defamatory, or otherwise controversial claims about a living person, relying solely on self-published sources is highly problematic. The subject may have a vested interest in presenting a favorable or biased account, and the lack of independent verification increases the risk of including inaccurate or misleading information. Therefore, such sources should only be used with extreme caution and corroborated by other, more reliable sources whenever possible. The burden of evidence is significantly higher for controversial claims in BLPs, and self-published sources rarely meet that standard on their own.