Consumer Price Dashboard methodology
How CPI series are selected and period changes are calculated.
Inputs and coverage
The dashboard uses selected Consumer Price Index series returned by the U.S. Bureau of Labor Statistics Public Data API. Series identifiers are pinned in configuration rather than discovered dynamically. This prevents an upstream catalog change from silently altering the meaning of a chart. We request a bounded ten-year window and preserve the official year, period, period name, value, and footnotes for every observation.
Change method
For each series, observations are ordered chronologically. The absolute change is the current index value minus the immediately prior reported index value. Percentage change divides that difference by the prior value and multiplies by one hundred. Annual periods and malformed values are not used as month-to-month comparisons. These calculations are produced by VUGA and are not BLS analyses.
Limitations
An index level is not a price in dollars, and a monthly percentage movement is not the same as a twelve-month inflation rate. BLS may revise seasonal factors and historical values. The public dashboard therefore displays source periods and retrieval context and links to the methodology rather than presenting the derived changes as forecasts or household-specific cost estimates.
Update schedule
The dataset is checked daily while new CPI observations generally arrive monthly. A retrieval that contains no changed values does not advance the visible modified date. If an ingest fails, the prior promoted snapshot remains published. Three consecutive scheduled failures pause ingestion and add a staleness notice without removing the static pages.