How the orchestrator works
Each indicator declares an ordered fallback chain. When you load a country, the orchestrator tries each source in turn: World Bank first for most macro variables, IMF DataMapper for forecasts and as a backup for fiscal/debt/inflation, OECD for confidence indicators on member countries, WHO Global Health Observatory for health series. The first source that returns data wins, and that source is stamped on the chart so you can see exactly where each number came from.
If you hit a chart that says NO DATA, every source in the chain returned empty for that country-year window — usually because the indicator genuinely isn't collected for that country, not because we failed to ask. Try the /api/debug/{iso3}/{indicator_id} endpoint to see the exact fallback attempts and their results.