The Questionnaire Data Dictionary (QDD) contains information required by Diet*Calc to interpret the data in a questionnaire data file. The data dictionary contains the following information:
- The file location of each coded response, that is, the column position of each field in the questionnaire data file.
- All information required by Diet*Calc to interpret the coded responses, including the frequency value associated with each code, and the database food or foods associated with each frequency.
Which QDD Should You Use?
QDDs are available for each of the NCI instruments. NCI-distributed QDDs are specific to the instrument (DHQ-II.2010) and scanning technology. If you make changes to the questionnaire or to the format of the data file, select one of our QDDs to use as a template. Start with the QDD which uses the same formatting scheme that you intend to use. Use the Data Dictionary Editor to make the appropriate modifications.
A code is assigned to each oval on the questionnaire. The codes are documented in the codebooks provided for each of the NCI questionnaires, but can be modified to fit your needs. Coding schemes may be viewed or edited from the Settings menu of the Dictionary Editor in Diet*Calc.
Analysis variables contain information required to analyze specific questions including the location of data fields, format information needed to interpret the data, and the linkage between the frequency questions and the foods in the database. When you make a change to the Diet History Questionnaire, you will need to create a new analysis variable, add a component to an existing variable, or remove a variable using the Dictionary Editor.