Electoral Districting Research Articles

The Statistical Basis of Decisionmaking in Electoral Districting

This paper is concerned with procedures for dividing electorates into constituencies or electoral districts. Two traditions for drawing boundaries are identified, the British procedure of using neutral decisionmakers (Boundary Commissioners), and the American procedure which allows politicians to draw boundaries and thus leads to gerrymandering. If a statistical approach which focuses on the very large number of alternative ways of dividing up an electorate is employed, these two types of decisionmaking can be seen in statistical and political perspective. The most surprising finding of this approach is that in terms of political effects American gerrymanderers and British Boundary Commissioners produce similar types of districting solutions.

A New Shape Measure for Evaluating Electoral District Patterns

The concept of shape is considered in abstract terms drawing on approaches outside the electoral districting literature. The concept is broken down into a series of four divergences from “compactness” relating to “elongation,” “indentation,” “separation,” and “puncturedness.” Given this conceptual framework, the use of shape measures in electoral districting is reconsidered and a new shape measure is proposed. This assesses the indentation of a district shape and is based on the internal angles within the shape. It is suggested that this measure may be particularly relevant to the evaluation of proposed new districting patterns. The technique is illustrated using proposed new Congressional Districts for Iowa.