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Understanding the Jurisdiction Summary

The Jurisdiction Summary is the main dashboard for any district in The Ballot Book. It's designed to give you a comprehensive, at-a-glance overview of a district's geography, electoral performance, and political leanings. This page is broken down into two main parts: an overview of the key components, and a detailed look at how we calculate our advanced metrics.

At a Glance: What's on the Summary Page

Key Insights

This top bar provides a high-level snapshot of the jurisdiction, including total population, voter registration, and the calculated partisan lean, giving you an instant feel for the district's core numbers.

Geographic Overview Map

The interactive map shows the precise boundaries of the jurisdiction. For areas with sub-districts (like supervisor districts within a county), you can often toggle between the "At Large" and "Districts" views.

Electoral History

This table shows how the district voted in recent, major statewide elections (like for President or Governor), displaying the winning candidate and their margin of victory in this specific district.

Typical Vote Share Range

This visualization represents the typical "floor" and "ceiling" of support for each major party in the district. It's a powerful tool for understanding a district's electoral tendencies. See how this is calculated below.

Ideology (Ballot Measures)

This section analyzes how the jurisdiction voted on key statewide ballot measures, providing a more nuanced view of the district's political identity beyond simple partisan labels.

How We Calculate Key Electoral Metrics

Partisan Lean

The partisan lean number is a weighted average of how this district voted in top-of-the-ticket statewide races over the past four election cycles. A positive number (D+) indicates the district tends to vote more Democratic, while a negative number (R+) indicates it tends to vote more Republican.

Calculation Method:

  • We analyze the margin between the Democratic and Republican candidates in statewide general elections for offices like President, Governor, and U.S. Senate.
  • Only races where both major parties fielded a candidate are included.
  • More recent elections are weighted more heavily to better reflect the current political climate:
    • Most recent cycle: 40% weight
    • Second most recent: 30% weight
    • Third most recent: 20% weight
    • Fourth most recent: 10% weight

Caveats: This metric is a powerful shorthand but has limits. It is based on statewide contests, which may not perfectly reflect voting patterns in local races. It is a snapshot based on past performance, not a prediction of future results.

Typical Vote Share Range

This range represents the floor and ceiling of electoral performance for each major party in the district. It is calculated by finding the lowest and highest vote percentages received by each party's candidates in the same set of statewide general elections used for the Partisan Lean.

  • A narrow range (e.g., 55% - 60%) suggests consistent, predictable voting behavior.
  • A wide range (e.g., 45% - 65%) might indicate a more volatile or "swing" district where candidate quality or campaign issues can have a larger impact.
Putting It All Together

By combining these elements, the Jurisdiction Summary page allows you to move from a broad geographic understanding to a deep, nuanced analysis of a district's political character. Each component is a piece of the puzzle, and together they provide a robust foundation for any political or policy research.