Replication Data for a Normalized Disproportionality Index

A political science dataset replicating analysis on the Gallagher index, a popular measure of electoral disproportionality. The author, Jack Bailey, demonstrates the index's maximum value is constrained by the number of effective parties and proposes a new normalized measure. The dataset was last updated on 2026-05-19 via Harvard Dataverse.

Use Cases

• Calculate disproportionality scores for elections based on the Gallagher index.
• Compare electoral outcomes across party systems of varying fragmentation using the proposed normalized index.
• Replicate the mathematical proof linking the Gallagher index's maximum value to the number of effective parties.
• Analyze trends in party-system fragmentation and its impact on measures of representation.

Strengths

• Dataset is associated with a formal academic note that includes a mathematical proof.
• The description explicitly addresses a known methodological limitation in a widely-used political science index.
• Last update timestamp (2026-05-19) is provided.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count and file size are unknown, which may limit suitability assessment.
• The dataset's specific electoral coverage (countries, years) is not detailed in the provided metadata.

Provenance

Source

Harvard Dataverse

Collection Method

Likely contains calculated index values and supporting election data for replication.

Freshness

Last updated 2026-05-19 02:26:30; freshness should be verified.