Setting up helper fields
A variable's HelperFields collection defines its associated variables: for example, text variables to hold the open-ended responses to Other Specify categories, numeric variables to hold multipliers, categorical variables to hold the coded responses of open-ended responses, categorical variables to hold special No Answer and Don't Know responses for numeric variables, and so on.
The FullName of the helper fields' Variable and VariableInstance objects contain the name of the parent variable, so it is not necessary to include the name of the parent variable in the names of the helper variables. For example, the text helper variable that holds the responses to an Other Specify category is typically called Other. For a categorical variable called Museums, the FullName of the Variable would be Museums.Other. If an additional helper field called Codes was created for the coded responses, its FullName would be Museums.Other.Codes.
When scanning a paper questionnaire, you might want to store the name of a .tiff file that contains an image of the scanned response. And in CATI interviewing, you might want to store the name of a sound file that contains the recorded verbal response. These helper variables are typically called SourceFile.
To create a categorical variable with an Other Specify category
1 Create the categorical variable (vcat), and then add it to the Document.Fields collection.
2 Create a text variable (other), and then add it to vcat.HelperFields.
3 Set the OtherReference property on the Other Specify category's to other.
MDM automatically sets the variable's usage type to vtOtherSpecify.
See also