Definition
Archival data comprise existing official records, documents, or databases systematically preserved by institutions or organizations for administrative or historical purposes, later reused by researchers for analysis.

Introduction
Not all research requires new data—sometimes the past speaks volumes. Archives hold a treasure of information waiting to be re-examined: company annual reports, court judgments, government files, even digital server logs. Studying them can illuminate long-term trends or verify contemporary patterns without additional fieldwork.

Explanation
Researchers consult physical archives (libraries, corporate records, national registries) or digital repositories (UN data, SEC filings, social-media archives). The process involves locating relevant documents, verifying authenticity, and coding qualitative or quantitative information.
For instance, a historian analyzing gender representation in newspapers might code thousands of past articles; a financial researcher might track twenty years of stock disclosures.

Archival research saves time and reveals longitudinal insights, but data may be incomplete, inconsistent, or biased toward the recorder’s viewpoint. Critical evaluation of source reliability and contextual understanding are indispensable.

Key Takeaways
Archival data extend the researcher’s reach across time, offering historical depth but demanding careful validation of source quality.

Real-World Case
Economists studying the Great Depression often rely on archival data from the U.S. Federal Reserve and historical price indices. Such secondary analyses have reshaped understanding of monetary policy failures and recovery mechanisms.
Reference: https://www.federalreservehistory.org