Database Access Functions
CRSPAccess items in the Stock & Index databases and the CRSP\Compustat Merged database can be identified with unique mnemonic text items name maintained by CRSP, called itm_name. Items can be further qualified by a set of secondary keys. CRSP calls these known collections of keys and values a keyset and assigns a numeric code and mnemonic tag to each unique collection. Each of these represents different output series. When multiple keysets are available, the user can specify both the item and keyset to identify a series or use the default preset combination most commonly used.
For example, the Compustat data item SALE has secondary keys for industry format, data format, population source, and consolidation level. A different value of company sales can be available for any combination of these keys, such as a combination that represents the originally reported sales or the final restated sales from a later filing.