Methodology & Sources

Every number has a source. Every source is named.

Baseline does not produce its own statistics. We select, simplify and present data from the world’s leading research institutions – and show you exactly where it comes from.

Our principles

Leading sources only International organisations, leading universities and peer-reviewed research – never anonymous or partisan sources.

The long view We compare today with decades or centuries, because slow change is invisible in daily news.

Honest about limits Historical values come from peer-reviewed reconstructions, and we name them. Where progress has stalled or reversed, we show that too.

Rounded for clarity Numbers are rounded and always show the year they refer to. Each page shows when it was last reviewed.

Where our data comes from

Our World in DataUniversity of Oxford / Global Change Data Lab – long-run data across all topics

World BankPoverty, income and development indicators

United NationsUN DESA population data, SDG reports, UNdata

World Health OrganizationHealth, vaccination and disease data

Maddison ProjectUniversity of Groningen – historical income data

Peer-reviewed researchStudies in journals such as The Lancet, cited individually

Licences

We draw our own charts from published data wherever possible. Third-party data and charts remain subject to the licence terms of their owners, and we credit both the publisher and the original data source. Most datasets we use – from Our World in Data, the World Bank, UCDP, V-Dem and the Maddison Project – are published under the Creative Commons BY 4.0 licence; some, such as the PRIO battle-death data, have their own terms of use.

Found an error?

We correct mistakes openly and note the date of every change. Please write to office@baseline-evidence.org.