▪Extract a single version of a questionnaire definition (.mdd) file and save it as a new questionnaire definition file. This is useful when a questionnaire definition has become very large because it has many versions but only the latest version is needed.

▪Merge two or more versions of a questionnaire definition (.mdd) file and save the result as a new questionnaire definition file. This is useful when you want to export case data for more than one version and there have been changes to the variable and category definitions, which mean that case data collected with one version is not valid in another version. Creating a version that combines the versions for which you want to export the case data, means that generally you can export the case data collected with the different versions at the same time without encountering validity errors due to the difference between the versions. However, depending on the version changes, some validity errors may still be encountered.