The Tau of Data: A New Metric to Assess the Timeliness of Data in Catalogues
We review existing studies that assess the timeliness of data in catalogues and propose a new metric: tau, the percentage of datasets up-to-date in a data catalogue. Obsolete data will stifle innovation, whereas spotlighting timeliness can foster efficiency and support the sustainability of the open data ecosystem, for example, by encouraging automated publication of data.We validate the tau in three case studies: the World Bank catalogue, the UK data catalogue ( and the London Datastore. For the World Bank and London we find that roughly half of the datasets are up-to-date, whereas performs worse. However, there are considerable caveats when it comes to missing and undocumented metadata. The tau of data is easy to implement, can be readily interpreted and be generalised with further parameters across all data catalogues. open data, timeliness, data quality, data catalogue, datastore

Ulrich Atz, Head of Statistics at the Open Data Institute (ODI)

Ulrich holds a Diploma in Economics from the University of Mannheim and a M.Sc. in Social Research Methods from the London School of Economics. He has a broad background that blends modern statistical techniques with practical uses of data. At the ODI, Ulrich leads research projects, consults startups and governments on the business case of open data, and helps out with training courses. He regularly holds presentations and keynotes.

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