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ALFRED, ArchivaL Federal Reserve Economic Data, is a collection of vintage versions of U.S. economic data.
In general, economic data for past observation periods are revised as more accurate estimates become available.
As a result, previous vintages of data can be superseded and may no longer be available from various data sources.
ALFRED makes it possible to gather data as reported by a source on past dates in history. The Research Division
hopes that ALFRED will provide users with the tools they need to reproduce past research, build more accurate
forecasting models, and analyze economic policy decisions of the past with data that were available at the time.
Please contact the Research Webmaster with questions and comments about ALFRED and vintage data.
Read Download Data Help for an explanation of the options on the download data form.
Research Division analysts monitor sources of economic data for scheduled and unscheduled releases of data. New and
revised observations are added to ALFRED as soon as possible following their release- typically within one business day.
A release is any mechanism that makes data available. The sources of most series in ALFRED issue scheduled press releases that
coincide with the release of new data. However, some sources make data available without a press release. Release dates are the dates
when new data first become available from a source.
Release dates are determined by the following process:
- When available, the actual release date as provided by the source is entered into the ALFRED database.
- If a release date is not available from the source, the release date given by our data providers is used.
- If a release date cannot be determined either from the source or from our data providers, the date that the series was first
available in the St. Louis Fed's FRED database is used.
When possible, vintage data in ALFRED are verified with the original source of the data. Please note
that many sources do not maintain previously published estimates. In this case, data are verified
using information from third-party data services.
For an introduction to ALFRED, view the presentation ALFRED: Capturing data as it happens.
For more about real-time data and ALFRED,
read Replicability, Real-Time Data, and the Science of Economic Research: FRED, ALFRED, and VDC
by Richard G. Anderson in the
2006 JANUARY/FEBRUARY issue of the
Federal Reserve Bank of St. Louis Review.
For more about the database concepts used to store real-time revisions, read chapters 1-7 in
Developing Time-Oriented Database Applications in SQL
by Richard T. Snodgrass.
For a description of the internal workflow used to load vintage data into ALFRED, read Populating an
Note that because ALFRED uses levels and rounded data as published by the source, calculations of percentage changes and/or growth rates in some series may not be identical to those in the original releases.
The following formulas are used:
x(t) - x(t-1)
Change from Year Ago
x(t) - x(t-n_obs_per_yr)
((x(t)/x(t-1)) - 1) * 100
Percent Change from Year Ago
((x(t)/x(t-n_obs_per_yr)) - 1) * 100
Compounded Annual Rate of Change
(((x(t)/x(t-1)) ** (n_obs_per_yr)) - 1) * 100
Continuously Compounded Rate of Change
(ln(x(t)) - ln(x(t-1))) * 100
Continuously Compounded Annual Rate of Change
((ln(x(t)) - ln(x(t-1))) * 100) * n_obs_per_yr
'x(t)' is the value of series x at time period t.
'n_obs_per_yr' is the number of observations per year. The number of observations per year differs by frequency:
Daily, 260 (no values on weekends)
'ln' represents the natural logarithm.
'**' represents to the power of.
The NBER recession data is available at http://www.nber.org/cycles.html. The monthly dates for the peaks and troughs are represented as daily dates in the charts as: