The 1978 CPI revision introduced probability sampling methods at all stages of CPI sampling.
Notes on verification
Multiple independent, high-quality sources (BLS research papers, IMF Consumer Price Index Manual, National Academies report) corroborate that the 1978 CPI revision introduced probability sampling at all stages of sample selection, consistent with BLS's own historical account. [tier=silver indep_score=0.925 clusters=2 claim_tier=notable]
Sources
- Chronology of changes in the Consumer Price Index (seed:economics_and_business)
- https://www.elibrary.imf.org/display/book/9789221136996/C05.xml (corroboration)
- https://www.nationalacademies.org/read/26485/chapter/4 (corroboration)