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Epidemiology and Genomics Research Program

Diet History Questionnaire: Missing and Error Codes

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 missing code indicates that the respondent skipped a question when a response was required. An error character indicates that the respondent marked two or more responses to a question where only one answer was appropriate. The following guidelines must be used for coding fields as missing or error.

  1. Letters or symbols (such as '*', '#', or '!' ) must be used as the missing and error characters. If letters are used to code formatted responses, symbols must be used for missing and error. Missing and error characters may never be numeric.
  2. When multiple characters are used to code a single oval, set all characters in the field to the missing character or to the error character when appropriate. For example, the year field in Today's Date uses one oval but is coded with four characters ("2002", "2003", etc.). If all choices are skipped, the entire field should be filled with the missing character ("MMMM", for example).

You may not use the same character to represent both the missing and the error characters. In the DHQ-1, 'M' and 'E' are the missing and error characters, respectively.