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Epidemiology and Genomics Research Program

Diet History Questionnaire: Coding Guidelines

Alternate Version Available

You are viewing the web site for the original version of the DHQ. The latest version for the U.S. is the DHQ III; however, DHQ III does not yet have a Canadian version. The Canadian version of DHQ II is still available.

A questionnaire data file is an ASCII text file containing data from completed Diet History Questionnaires. If using paper forms, this file can be created by a scanner or a data entry system. If using DHQ*Web, the questionnaire data file is created automatically. Each line in a questionnaire data file contains the coded responses for one questionnaire. The format of each line of data is specified in the questionnaire's codebook (a readable format) and in the questionnaire data dictionary (used by Diet*Calc). Codebooks and data dictionaries for NCI versions of the questionnaire designed for specific scanners or for data entry are provided in the DHQ Paper-based Forms.

Questionnaire data analyzed by Diet*Calc must be coded according to the guidelines described here. These guidelines apply to all NCI versions of the DHQ and to modified versions of the DHQ that you create. Follow these guidelines when developing new questions for the instrument and when configuring your scanner or data entry system.

The codebooks for the NCI versions of the questionnaire were created in wordprocessing software. The same information is stored in the Questionnaire Data Dictionary (QDD) used by Diet*Calc. The information in the QDD can be printed from Diet*Calc. However, the current version of the software provides a limited amount of detail in this report. It was designed to provide a report of potential problems in the QDD and does not provide column-by-column coding information that can be used by a programmer to configure a scanner or data entry system. If you modified the questionnaire then you should consider creating a codebook specifically for your instrument. The codebooks for the NCI versions of the questionnaire are provided in generic file formats so that they can be edited in any wordprocessing package.

The following sections summarize the coding guidelines that must be used for DHQ data: