A calculation base allows a user to create a filter for the question’s total base by using a definition of responses from one or more separate questions. Only respondents who meet the definition of the calculation base will be included in the “based” question. The purpose of using a calculation base is to limit the base of respondents of a question to only those who are qualified to answer. This is determined by the responses given to separate, related questions (i.e. whether or not a respondent is included in the question that has a calculation base applied is contingent on how they answered a separate question). Some examples for applying a calculation base to a question are:
Satisfaction with the vehicle manual transmission
(calculation base: new vehicle purchased transmission = “manual”)
Types of liquor typically consumed in the past 3 months
(calculation base: respondent age = “21+”)
Number of problems with the new vehicle
(calculation base: experienced any problem(s) with the new vehicle = “yes” )
The calculation base is set in the Details section of the Data Import editor.
A “not restricted” status is displayed by default if the question does not currently have a calculation base applied.
Click Edit to define the calculation base for the question.
The interface is similar to what is already used for creating UDQs.
After selecting a question, subset on one or more responses to define the calculation base.
Repeat the steps of selecting another question and subsetting on responses if the calculation base definition should include multiple questions.
After completing the calculation base definition, the status will change to display the question(s) used in the definition.
This question is now based and by nature of a based/filtered question, a reduced sample size for the question will be reflected in the results.
Note: The custom calculation base definition is kept separately for each dataset containing the question (e.g., it's possible to have different base conditions for the same question across different datasets, or have no custom base in one dataset while the same question has custom base in another dataset).
Calculation base definitions can only include single choice category questions or numeric questions.
Multichoice or verbatim questions are not compatible with the calculation base.
If a calculation base definition becomes invalid (e.g., one of the questions in the based definition no longer exists), then the question with the calculation base will show an error and will need to be corrected.
