An examiner can take official notice without documentary evidence in certain circumstances where the facts are considered well-known or common knowledge in the art. According to MPEP 2144.03, this is permissible when the facts are "capable of instant and unquestionable demonstration as being well-known." The MPEP states: "Official notice without documentary evidence to support an examiner's conclusion is permissible only in some circumstances. It is always preferable, when reasonably possible, for the examiner to cite a prior art reference rather than to rely on official notice." However, examiners should use this judiciously, especially in final rejections or actions under 37 CFR 1.113. To learn more: official notice patent examination common knowledge well-known facts