A document which lists the variables in a dataset, possible values for each variable, and the definitions of codes that have been assigned to these values.
Generically, any information on the structure, contents, and layout of a data file. Typically, a codebook includes: column locations and widths for each variable; definitions of different record types ; response codes for each variable; codes use to indicate non-response and missing data; exact questions and skip patterns used in a survey; and other indications of the content of each variable. Many codebooks also include frequencies of response. Codebooks vary widely in quality and amount of information included. They may be machine-readable or paper copy or microfiche.