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Harmonised Variables – Combining survey data more easily through standardised and harmonised variables

Unlocking the potential of survey data from multiple sources by achieving their interoperability.

Survey programs are creating ever-growing volumes of valuable data. To fully unlock their potential, these data must be made findable, accessible, interoperable, and re-usable (in line with the FAIR principles). The interoperability of survey data, however, continues to be an obstacle: Different instruments are used to measure identical concepts. This renders survey data less comparable and less combinable. Combining survey data, however, creates great opportunities: it could help extending time series, exploring interesting subpopulations with adequate (combined) sample sizes, and making research results more robust and reproducible with integrative meta-analyses.

The Harmonised Variables Service will help to unlock this potential by increasing the comparability of measurement instruments and the data collected through them. Firstly, we will support data producers during the questionnaire design stage by developing best practice guidelines for measuring socio-demographic characteristics. Secondly, we will create transformation tables and scripts for research data centres and data users. The latter make existing data on different characteristics comparable, i.e., harmonising data ex-post.

For use on latent constructs (e.g., attitudes, interests, or values), we will create QuestionLink, a harmonisation database. It will allow users to efficiently harmonise data for selected constructs from all participating surveys and across all the used measurement instruments. In addition, we will develop accessible education and training materials on QuestionLink as well as on methodological innovations in ex-post harmonisation of latent constructs in general.

QuestionLink will go online with the first harmonised construct (“political interest”) in the course of 2021.