A New York music store owner named Samuel C. Jollie created a glass ballot box, bringing literal transparency to the voting process. Voters inserted ballots through a small hole on the top of the box so that all ballots were visible.
- This indicator was developed to encourage inquiry into the significant causes of World War I and the factors leading to U.S. involvement. This indicator was also developed to promote inquiry into the effects of the war, to include its impact on the homefront, migration patterns, and continued foreign policy debates.
- This indicator was developed to encourage inquiry into the causes of American expansion, such as a growing and diversifying population and the expansion of the plantation economy. This indicator promotes inquiry into the relationship between sectionalism and political compromise, culminating in the Civil War.