  The efficiency gap formula was introduced in to measure political
gerrymandering. It played a key role in the Gill v. Whitford case whose appeal
is currently before the Supreme Court, but it was very recently shown by
Bernstein and Duchin to have some problematic mathematical properties. We
propose a new relative version of the efficiency gap formula that inherits its
desirable but not its undesirable features. Instead of measuring the difference
between the number of votes wasted by the two parties, we measure the
difference between the proportions of their votes that the two parties wasted.
