CRAAP is an acronym for Currency, Relevance, Authority, Accuracy, and Purpose. Use the CRAAP Test to evaluate your sources.

Currency: the timeliness of the information

Relevance: the importance of the information for your needs

Authority: the source of the information

Accuracy: the reliability, truthfulness, and correctness of the content

Purpose: the reason the information exists

Boolean operators and nesting help you search for combinations of words or phrases processed in a specified order. Boolean operators are supported in Advanced Search and the EXPERT option of Keyword Search. Keyword (EXPERT) also supports nesting. In the LC Catalog, Boolean OR expressions are executed first, followed by expressions using AND or NOT (which are considered equivalent). Processing of equivalent expressions takes place in a left-to-right (or top-to-bottom) sequence.

Boolean operators AND, OR, and NOT can be searched as keywords. In Keyword Search, just enter these terms in the search box. In Keyword (EXPERT) search, include these terms, along with other words, in quotes as a phrase. Boolean operators can be entered in either upper or lower case.

From the Library of Congress

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