SOFTWARE AND DATA CONVERSION

Digital information is designed to be interpreted by computer programs that render it understandable to human users and is, by its nature, software-dependent. The logical format of the data is thus endangered by loss and obsolescence of the hardware and software environment on which access to data depends. Despite the backward compatibility that many application software packages offer (and also interoperability between competing popular software programs) the safest option for long-term sharing is conversion to standard formats that most software is capable of interpreting and that are suitable for data interchange (data migration). UKDA adopts this strategy.

Your choice of software for data collection or analysis depends on how you wish to analyse data. In order to make data shareable, the best option is to choose a software program that can export to one of the data formats preferred by the UKDA

Conversion issues and tools

Statistical, spreadsheet and database packages all have slightly different data handling limits, which may also differ from the limits imposed by Computer Assisted Interviewing (CAI) software such as BLAISE. These differential limits mean that some data or internal metadata (missing value definitions, variable labels, etc.) will inevitably be lost upon translation. Data should be exported by data managers or other project staff familiar with the data, who should check for errors or inadvertent changes to the data that may occur in the export process. All recommended formats are subject to change over time as new archival and interchange formats are developed. UKDA has been working on tools for XML representation of data in ASCII and XML using the DDI. See DExT.

Qualitative data: CAQDAS products

Qualitative software packages, or Computer-Assisted Qualitative Data Analysis Software (CAQDAS), such as NUD*IST, ATLAS-ti and WinMax, have export facilities that enable a whole 'project' consisting of the raw data, coding tree, coded data, and associated memos and notes to be saved.

For archival purposes the raw data, the final coding tree and any useful memos should be exported prior to acquisition. Coded data are not preserved as they cannot, as yet, be exported in a common non-proprietary format.

ESDS Qualidata is working to encourage the development of data documentation standards using XML. The DExT work has proposed an XML schema, QuDEx, to represent annotated and complex multimedia data. At present, coded data are requested infrequently, mainly because the coding process is subjective, often geared towards specific themes, and therefore may not be applicable to the secondary analyst's topic of investigation. However, this is changing and access to coding schemes can be valuable for teaching and other forms of re-use. For larger studies, there is a stronger case for retaining coded data in order to aid searching within large bodies of text. However, this will always be an adjunct to the main body of raw data.