The review uses a frozen evidence-chain methodology. Edge definitions were set before analysis, applied independently per country and kept separate from implementation quality judgments.
The methodology exists so institutional, policy and academic reviewers can inspect what was measured and what was deliberately not claimed.
Two or more independent sources, an explicit link and no counterevidence.
Evidence exists, but the chain is incomplete or supported by fewer than two independent sources.
No identifiable public evidence after systematic search.
An independent source shows an explicit problem with enough detail to quantify the break.
The sample was selected to represent diversity in income class, WHO region and source coverage environment.
Source locators, evidence spans and reasoning notes are documented in an evidence ledger. The full reproducibility package is available upon request.