Legal Definitions - scatter-point analysis

Scatter-point analysis is a statistical method used to examine whether there is a relationship between the racial or ethnic composition of a voting area and the voting patterns observed in that area. It involves plotting data points on a graph, where each point represents a different voting precinct, district, or county. One axis of the graph typically represents the percentage of a specific racial or ethnic group within that area, while the other axis represents the percentage of votes a particular candidate received, or the percentage of votes for or against a specific ballot measure. By visually inspecting the distribution and trend of these points, analysts can determine if a candidate's performance or a ballot measure's support tends to increase, decrease, or show no clear correlation as the proportion of a particular racial or ethnic group changes.

• Example 1: City Council Election

  Imagine a city council election where Candidate A is running. Researchers want to understand if Candidate A's support varies depending on the percentage of voters identifying as Hispanic in different city wards. They would conduct a scatter-point analysis by plotting each ward on a graph. The horizontal axis might represent the percentage of Hispanic residents in a ward, and the vertical axis would show the percentage of votes Candidate A received in that ward. If the plotted points generally trend upwards from left to right, it suggests Candidate A tends to gain more support in wards with higher Hispanic populations. Conversely, a downward trend would indicate less support, while a scattered pattern might suggest no clear relationship.

• Example 2: School Bond Referendum

  A local school district is holding a referendum to approve funding for new school facilities. Community organizations are interested in whether support for the bond issue differs across precincts based on their demographic makeup. Using scatter-point analysis, they could plot each voting precinct. One axis would show the percentage of Asian American residents in a precinct, and the other axis would display the percentage of "yes" votes for the school bond in that same precinct. This visual tool would help them observe if precincts with a higher proportion of Asian American residents consistently vote more favorably or unfavorably for the bond, or if there's no discernible pattern linking the two variables.

• Example 3: State Legislative Race

  In a state legislative election, a political science team is studying the performance of an incumbent candidate across various precincts within their district. They want to investigate if the incumbent's vote share is influenced by the proportion of African American voters in each precinct. A scatter-point analysis would involve creating a graph where each point represents a precinct. The percentage of African American voters in a precinct would be plotted on one axis, and the incumbent's vote percentage in that same precinct would be plotted on the other. By examining the overall distribution and direction of these points, the team could visually assess if the incumbent's support tends to increase, decrease, or remain relatively independent of the percentage of African American voters in a given precinct.