Benefits of DDI

The DDI facilitates:

  • Interoperability. Codebooks marked up using the DDI specification can be exchanged and transported seamlessly, and applications can be written to work with these homogeneous documents. 
  • Richer content. The DDI was designed to encourage the use of a comprehensive set of elements to describe social science datasets as completely and as thoroughly as possible, thereby providing the potential data analyst with broader knowledge about a given collection. 
  • Single document - multiple purposes. A DDI codebook contains all of the information necessary to produce several different types of output, including, for example, a traditional social science codebook, a bibliographic record, or SAS/SPSS/Stata data definition statements. Thus, the document may be repurposed for different needs and applications. Changes made to the core document will be passed along to any output generated. 
  • On-line subsetting and analysis. Because the DDI markup extends down to the variable level and provides a standard uniform structure and content for variables, DDI documents are easily imported into on-line analysis systems, rendering datasets more readily usable for a wider audience. 
  • Precision in searching. Since each of the elements in a DDI-compliant codebook is tagged in a specific way, field-specific searches across documents and studies are enabled. For example, a library of DDI codebooks could be searched to identify datasets covering protest demonstrations during the 1960s in specific states or countries.