Seasonal adjustment: matching the comparison to the question

Methodological reference; no current numerical release

Research question

Which inflation series is appropriate for a short-term comparison?

BLS provides adjusted and unadjusted CPI series. Seasonal adjustment addresses recurring seasonal effects; seasonal factors are revised.

Record the series, adjustment basis and release vintage alongside every observation.

Do not splice seasonally adjusted and unadjusted observations into one growth calculation.

When a historical result changes, check whether the underlying series or seasonal factors were revised.

Seasonal adjustment does not remove all economic noise. This note contains no current inflation number.