This section describes the CRSP Link and Compustat variables and structures supported by the CRSP/Compustat Merged database. For complete definitions, codes, and formulas for Compustat items, see the documentation and resources provided to you by Compustat.
Compustat data are organized by company and security around Compustat’s Permanent SPC Identifier, GVKEY, and issue identifier, IID. Secondary identifiers are available in the header and link history that can be used to cross-reference companies to GVKEYs.
A defined structure for Compustat data is used to store all available Compustat and CRSP Link data for a GVKEY. Each structure is broken down into items. All structures are built from three basic data categories: headers, event data arrays, and time series.
- Headers have no time component. They are a collection of data items with one instance for each GVKEY. Examples of header data items are current identifiers and date ranges.
- Event data arrays are collections of records, each describing a change in status or a new event. All data items describing the event type are included in each record. These always include one or more data items that describe the effective date range or the effective date of the event. A count of the number of events being referenced is available for each event data array.
- Time-series is a collection of records tied to a specific calendar of time periods. Each time-series has a beginning and ending period and exactly one record of information for each period in that range. A time-series record can include one or more data items describing the period.
The data items defined within each data category are determined by the available Compustat or CRSP Link data for that data type.
Data definitions include data items provided by Compustat as well as structures and supplementary data items provided by CRSP. All data items include a mnemonic and field name. With the exception of roughly a dozen data items, the mnemonics of Compustat data items used in the CCM database match the name provided by Compustat. No further definitions for Compustat data items are provided in this guide except clarification on mnemonics and usage for a data item that may be used differently by Compustat in different files. For additional help, visit the Compustat support page. Supplementary CRSP data items include complete definitions.
Implicit in every structure is CCMID, which may be PERMNO, GVKEY, or GVKEYX, depending upon what identifier key is needed for data access. GVKEY is a unique permanent number assigned by Compustat, that can be used to identify a Compustat record in different updates if name or other identifying information changes. GVKEY is the primary key in the CRSP/Compustat Merged Database. Data are sorted and organized by this field.