When our sources changed underneath us

A series can change meaning on a date with nothing on the chart to say so: the source changed its file format, how it counts, or what a field means. Each break below has a page with the date, the size of the effect as we measured it, and what we did: recount the history, withhold what we could not trust, or switch to another route to the same source. Charts that show an affected series draw a dashed line on that date and link here.

An entry is added when a break is measured, not suspected. The data sources page lists every source and its delay, and the ingestion ledger lists every failed run.