Released to the public seventy-two years after the information is collected.

Source of historical evidence produced by social systems that captures the actions of ordinary people and provides information about social structure and social change.

Analytical historians usually rely on this.

Systematic description of the symbolic content of communications.

Allowing congressional members to edit proofs creates this problem for the Congressional Record.

Use of historical events and evidence to develop or test social theory.

The object that is coded in a content analysis.

Major advantage that physical evidence and other available data sources have over experiments and surveys.

Frequently cited characteristics are its volume, velocity, and variety.

Source of historical evidence that focuses analysis on the activities and motivations of individual actors.

Data collected from the registration of births, deaths, marriages, and divorces.

Repositories of data from surveys and ethnographies.