An MDD file is typically used to represent the survey questions and the routing between the questions. Because the MDM object model is the only official method for interacting with the MDD file, and the object model only runs on Windows based operating systems, the information in the MDD file must be transformed into another format. The transformation must occur on a machine that is running the MDM object model (for example, in MobileSyncWebServiceA.

A single MDD file typically stores all survey information, for multiple languages, in different contexts (interviewing versus analysis), across multiple versions. TheMobileSyncWebService returns an XML representation of the survey, but only for a specific version, in a single language, and only for a single context (Question for example). The MDD file contains both the question definitions and the routing information, but the information is separated into two different XML types (Question XML and RoutingXML).

This transformation is implemented by using a write-only C# MDSC called the SurveyQuestionXML MDSC. The MDSC writes information by using the currently selected Version and LCL. It requires options to write the Question XML, RoutingXML, or both. The MDSC options can be further specified during the implementation phase.

The Question XML and RoutingXML schemas provide optional attributes and their default values. Any attribute that is equal to the default value is not included in the MDSC produced XML.