The Open Data Barometer – Leaders Edition is based on three kinds of data:

• A peer-reviewed expert survey carried out between December 2017 and March 2018, with a range of questions about open data contexts, policy, implementation, and impacts and a detailed dataset survey completed for 15 kinds of data in each government, which touched on issues of data availability, format, licensing, timeliness, and discoverability
• A government self-assessment simplified survey carried out between September and November 2017 with the same range of context, implementation, and impacts questions, as an additional source of information.
• Secondary data selected to complement our expert survey data. This is used in the readiness section of the Barometer, and is taken from the World Economic Forum, International Telecommunications Union, United Nations e-Government Survey, and Freedom House.

This edition of the Open Data Barometer seeks to repeat the analysis from previous editions, with some minor methodological revisions and two major modifications:

• The scope of the study has been reduced, now measuring 30 governments only — those that have publicly committed to adopt the International Open Data Charter Principles or the equivalente G20 Anti-Corruption Open Data Principles.
• We are using absolute values in the 0-100 scale for scores now — rather than the previous scaled values — to provide more realistic evaluations of performance. However, to allow for direct historical comparisons, we are providing recalculated absolute values as well as scaled values for all previous editions on our website.

Overall, however, we have sought to maintain certain consistency with the questions used in previous editions. Wider methodological revisions will continue to be explored in future editions as we keep improving our measurement methods as part of our work in the Open Data Charter measurement and accountability working group.

You can read more about the methodology and research process and method in the detailed methodology description (pdf version) and the research handbook (pdf version). Feel also free to provide your feedback through comments on the respective online versions. Historical and comparable consolidated (absolute and scaled) data for all Barometer editions is available on the website.