Setting up basic questions

When you add the variable to the Document, MDM creates a VariableInstance object, which represents the data storage for the question. If the variable is part of a loop or a grid, or has helper fields, there can be more than one VariableInstance object for the question. MDM generates a unique FullName for each VariableInstance, based on its place in the Document. If these FullNames are unsuitable for your data source, you need to set up alias names on the VariableInstance objects.

The variable's Labels property enables you to store a matrix of texts. The following table provides some examples of how this works for the base language. Translations of each of these text can be stored in each language defined in the Document.Languages collection.

User context	Label type	Typical use	Example
Question	Label	Question text	What type of school or college do you attend?
Question	Shortname	Short question name	Q5
Question	Instruction	Instruction to interviewer / respondent	Only if answered Yes to Q4
Analysis	Label	Variable description for use during analysis	School or college type
Analysis	Shortname	Not applicable
Analysis	Instruction	Not applicable

Data type constant	Description
mtCategorical	Categorical variable
mtDate	Date and time stored in standard Microsoft format
mtDouble	Real (decimal) numbers
mtLong	Integer numbers
mtNone	The variable does not store data
mtText	Text variable
mtObject	BLOB data, such as images of scribbled responses and voice recordings
mtBoolean	Boolean variable

Data type	MinValue	MaxValue
mtCategorical	Specifies the minimum number of responses that must be selected. A value of 1 indicates that at least one response must be selected. A value of 0 indicates that the respondent does not have to select a response.	A value of 1 indicates that this is a single response question. A value greater than 1 indicates that this is a multiple response question. For a multiple response question, MaxValue should indicate the maximum number of responses a respondent can choose. This is typically, but not always, the number of responses in the question.
mtDouble	Indicates the lowest valid value.	Indicates the highest valid value.
mtLong	Indicates the lowest valid value.	Indicates the highest valid value.
mtNone	You do not need to specify MinValue because the variable will not store data.	You do not need to specify MaxValue because the variable will not store data.
mtText	Specifies the minimum number of characters allowed.	Specifies the maximum number of characters allowed.

7 If you want to add categories to other types of variables (for example, to store coded responses, or to represent Don't Know or Refused to Answer categories), you must create them as separate categorical variables, which you then add to the variable's HelperFields collection. For more information, see Setting up helper fields.