Economic data vintages: what was knowable then?

Latest history and historical knowledge are different objects

A current chart can show a refined estimate of an old period. That does not establish the value available when a trader made a decision. Save the original producer, series identifier, units, geography, reference period and the vintage being consulted. A document capture date is another field rather than a substitute for official availability. A historical story should make clear whether it uses latest descriptive history or an as-of information set. The distinction matters even if both calculations are numerically correct: they answer different questions about the past.

Keep predecessor and successor releases

Preserve the earlier level and the later revised level for the same reference period. Their difference is a revision, not a new period of economic activity. Methodology, seasonal adjustment and scope can change too, so equality of series names is not sufficient comparability. Record the source's own revision notes and retain inaccessible versions as gaps. Do not generate plausible vintage values from a latest chart. A complete-looking history reconstructed after the fact cannot prove the earlier information set was causal or that a subscriber saw the source then.

A vintage archive has a bounded role

ALFRED describes retrieval of historical release vintages. The original producer still defines what the series measures and how revisions work. A vintage mechanism does not certify every transformation a writer applies, supply an actual trading fill or make an arbitrary benchmark appropriate. For a real article, link the specific source object and transformation, not just the archive home page. The teaching workbook supplies no genuine agency observations or authentic release times. Its named steps are documentation examples rather than records of a completed economic-data investigation.

Freeze the information question before evaluating a thesis

Write whether the thesis concerns growth, price level, policy reaction or market expectation, then identify the series that could contradict it. A later revision can change the historical economic interpretation without change the decision information that was actually available. Report those impacts separately. Actual strategy research must preserve its authoritative source route and independent completion, rather than replace causal inputs with attractive hindsight values. A source-informed editorial can remain useful without claiming it ran that research or measured a profitable response to the release.

Authored editorial case

Authored case: SOURCE-A initially describes a prior level as 100; a later teaching release changes that same period to 102 and adds a new-period value of 103. No real series, vintage date or producer payload is supplied. The packet keeps both prior values rather than silently overwrite 100. A real feature would need exact release files, original availability and definition continuity before calling the new comparison causal historical evidence. Missing source identity remains a documented request, not an invented GDP observation.

Primary mechanisms and evidence scope

Source desk review: 14 October 2026. These primary destinations define their own statistical, account or publication objects. They do not document an FTM interview, respondent panel, private audit or successful trade. Exact values need their own original release, units, vintage and access record.

• St. Louis Fed ALFRED vintage archive
• BEA national-account methodologies