The type of data collection instrument used. "Structured" indicates an instrument in which all respondents are asked the same questions/tests, possibly with precoded answers. If a small portion of such a questionnaire includes open-ended questions, provide appropriate comments. "Semi-structured" indicates that the research instrument contains mainly open-ended questions. "Unstructured" indicates that in-depth interviews were conducted. The use of the attribute "type" as a means of specifying a controlled vocabulary concept is DEPRECATED. To specify the use of a Controlled Vocabulary or standard concept use the internal element "concept". DDI provides a Controlled Vocabulary for this location: "TypeOfInstrument". If multiple concepts are needed the parent element should be replicated. Internal text related to each concept should be allocated to accompany the relevant concept.