series definition

Series in FRED®

What is a Series?

In FRED®, a series is a named sequence of economic observations measured over time.

Each series represents a single economic variable, such as:

  • Gross Domestic Product (GDP)
  • Consumer Price Index (CPIAUCSL)
  • Unemployment Rate (UNRATE)
  • Federal Funds Rate (FEDFUNDS)

A series is the fundamental unit of data in FRED.

Each observation within a series consists of:

  • A date
  • A value
  • Associated metadata (units, frequency, seasonal adjustment, source)

Why Series Matter in Economic Analysis

Series are the primary inputs to all economic analysis.

They allow economists to:

  • Track changes over time
  • Measure trends and cycles
  • Compare economic indicators
  • Build statistical models
  • Construct derived metrics (e.g., growth rates, volatility)

Because FRED aggregates data from many sources, each series provides a standardized, time-indexed view of a specific economic concept.


Components of a Series

Each FRED series includes:

ObservationsTime-indexed data points (e.g., monthly CPI values)
FrequencyDaily, weekly, monthly, quarterly, or annual
UnitsLevels, percent change, logarithms, etc.
Seasonal AdjustmentAdjusted or not adjusted for seasonal effects
SourceThe originating institution (e.g., BLS, BEA, Federal Reserve)
Release InformationThe dataset or publication the series belongs to
These attributes define how a series should be interpreted and used.

Series vs. Observations

ConceptDescription
SeriesA named time series (e.g., CPIAUCSL)
ObservationsIndividual data points within the series

Example: CPI (CPIAUCSL)

The Consumer Price Index for All Urban Consumers (CPIAUCSL) is a monthly series.

It includes:

  • A time series of price levels
  • Monthly frequency
  • Seasonally adjusted values
  • Units in index level
  • Economists use this series to:
  • Measure inflation
  • Compute year-over-year changes
  • Compare price dynamics over time

Example: Unemployment Rate (UNRATE)

The Unemployment Rate (UNRATE) is another widely used series.

It provides:

  • Monthly unemployment percentages
  • Seasonally adjusted data
  • A key indicator of labor market conditions
  • This series is often used in:
  • Macroeconomic analysis
  • Policy evaluation
  • Business cycle research

How Economists Use Series in Practice

In research workflows, series are used to:

  • Construct time-series models
  • Compare multiple indicators
  • Build dashboards and reports
  • Analyze structural changes in the economy
  • Feed into forecasting and policy models
  • Series are often combined with:
  • Tags (for filtering)
  • Categories (for navigation)
  • Transformations (for analysis)

Summary

A series in FRED is a time-indexed sequence of economic data representing a single variable.

It allows economists to:

  • Measure and analyze economic activity over time
  • Compare indicators across domains
  • Build reproducible analytical workflows

Series are the foundation of all data in FRED.



Explore Series in RESERVE CLI

No affiliation with the Federal Reserve Bank of St. Louis

Not endorsed nor supported by the FRED® API technical team

© 2026 Derick Schaefer