The Polsby–Popper test is a mathematical
compactness measure of a shape
The compactness measure of a shape is a numerical quantity representing the degree to which a shape is compact. The meaning of "compact" here is not related to the topological notion of compact space.
Properties
Various compactness measures are us ...
developed to quantify the degree of
gerrymandering
In representative democracies, gerrymandering (, originally ) is the political manipulation of electoral district boundaries with the intent to create undue advantage for a party, group, or socioeconomic class within the constituency. The m ...
of political districts. The method was developed by lawyers
Daniel D. Polsby and Robert Popper, though it had earlier been introduced in the field of paleontology by E.P. Cox. The formula for calculating a district's Polsby–Popper score is
, where
is the district,
is the perimeter of the district, and
is the area of the district. A district's Polsby–Popper score will always fall within the interval of