Documenting a Wider Variety of Data Using the Data Documentation Initiative 3.1

This paper looks at the growing variety of data sources in research that are not traditional question-based surveys, and how these can be usefully documented using version 3.1 of the Data Documentation Initiative. These data are increasingly being linked with data collected from more traditional surveys to bring multidisciplinary perspectives to bear on research questions. This phenomenon is not specific to longitudinal studies, but is a common issue in longitudinal contexts.  The category of non-survey data is broad and not easily defined. Examples of these types of non-survey data sources include (but are not limited to): administrative, health records, and register data; audio and visual data; batteries or simple scales yielding scores; and data generated by independent hardware instrumentation. The collection of biological measures and physical samples is also included in this category. This short list of non-survey data was not exhaustive; indeed, these data come from a variety of other disciplines and industries not mentioned explicitly here. Not all possible data sources can be anticipated; this is a rapidly evolving field. However, there are enough real-world examples to formulate best practices concerning the documentation of these data. This paper provides guidance on expanding the capability of the Data Documentation Initiative (DDI) standard to document a wider variety of data resources and suggests improvements that may be incorporated into the DDI standard in future versions.