[EL] Gerrymandering, the wasted votes / efficiency method, and geographic concentration

Sat Jun 17 15:07:28 PDT 2017

Additionally, it's important to avoid conflating partisan symmetry and
competitiveness. The courts have held that there's nothing wrong with
creating uncompetitive plans that treat the major parties symmetrically
(see Gaffney v. Cummings). The crux of a partisan gerrymander is partisan
asymmetry, not a lack of competitiveness. Fortunately, all of the standard
measures of partisan symmetry (including but not limited to the efficiency
gap) are conceptually and empirically distinct from competitiveness.

On Sat, Jun 17, 2017 at 2:59 PM Eric McGhee <mcghee at ppic.org> wrote:

> Sensitivity testing can identify such plans ("dummymanders" as Bernie
> Grofman has called them). We cover that topic at length in the Chicago Law
> Review piece, and the plaintiffs have taken it very seriously as well.
> Thus, while technically one *can* calculate the EG without such analysis, I
> wouldn't recommend it or you might be surprised by plans like this.
>
> Eric McGhee
>
> Sent from my iPhone
>
> On Jun 17, 2017, at 2:45 PM, Daniel A. Smith <dasmith at ufl.edu<mailto:
> dasmith at ufl.edu>> wrote:
>
>
> I've always been perplexed by the logic of the efficiency gap...
>
> Nick and Eric provide an example of how the efficiency gap works in their
> Chicago Law Review article.
>
> They write (p. 851-852) (notes and italics omitted):
>
> The efficiency gap, then, is simply the difference between the parties’
> respective wasted votes, divided by the total number of votes cast in the
> election. Wasted votes include both “lost” votes (those cast for a losing
> candidate) and “surplus votes” (those cast for a winning candidate but in
> excess of what she needed to prevail). Each party’s wasted votes are
> totaled, one sum is subtracted from the other, and then, for the sake of
> comparability across systems, this difference is divided by the total
> number of votes cast. Figure 1 below shows how this calculation is carried
> out for the hypothetical district plan discussed in the Introduction. The
> bottom line is that there are 200 fewer wasted votes for Party A than for
> Party B (out of 1000 total votes), resulting in an efficiency gap of 20% in
> Party A’s favor.
>
> Here's their Figure 1:
>
>
> <fekjibkodaaonkda.png>
>
> Let's leave aside for a moment some of the assumptions that go into
> calculating the efficiency gap and the creation of their table (such as no
> minor party candidates contesting the 10 seats, or that each seat actually
> has two candidates on the ballot (as opposed to uncontested seats that have
> to have imputed result totals)).
>
> Let's instead fill in the table with what on the face seem to be very
> competitive districts: Every seat is decided by just 2 percentage points,
> but Party A wins each of the 10 districts, 51% to 49%.
>
> Sure, Party B loses all the seats, but they all are competitive; each of
> the seats could potentially flip to Party B in subsequent elections.
>
> If I were Party B, or a candidate or supporter of Party B, I'd take these
> districts any day of the week.  Even if Party A strategically gerrymandered
> them, each district is winnable given a wave election, the right
> candidates, better messaging, higher (or lower) turnout, etc.
>
> Yet, the efficiency gap in my hypothetical scenario is 48%, more than
> twice that of Nick and Eric's example. Despite the overall competitiveness
> of my example, it would be a clear target for litigation according to the
> efficiency gap logic.
>
> I guess my question to Eric and Nick and the broader listserv is, how does
> the efficiency gap serve as a useful step in identifying a partisan
> gerrymander given this obvious flaw?
>
> dan
>
> --
>
> daniel a. smith, ph.d.
> professor & university of florida research foundation professor
> political science internship program coordinator
> department of political science
> 303 anderson hall              |  phone: 352-273-2346
> po box 117325                  |  fax:   352-392-8127
> university of florida          |  email: dasmith at ufl.edu<mailto:
> dasmith at ufl.edu>
> gainesville, fl 32611-7325     |
> http://people.clas.ufl.edu/dasmith/dasmith/<
> http://people.clas.ufl.edu/dasmith/dasmith/>
>
> https://twitter.com/electionsmith<https://twitter.com/electionsmith>
>
> On 6/16/2017 7:21 PM, Eric McGhee wrote:
> I invented the efficiency gap, yet I would still agree with Michael that
> it seems unlikely a ruling for the plaintiffs in Whitford would rely
> exclusively on that metric.  (I would take issue with Michael’s claim that
> the efficiency gap is a “simple transformation” of existing measures under
> all conditions, but that’s another story.)  It’s also worth noting that the
> legal standard Nick Stephanopoulos and I proposed (see
> http://chicagounbound.uchicago.edu/uclrev/vol82/iss2/4/<
> http://chicagounbound.uchicago.edu/uclrev/vol82/iss2/4/>) would still
> treat a plan’s observed efficiency gap as only one step in a process that
> would also allow a state to defend its plan as unavoidable for other
> reasons.
>
> Fortunately for the Whitford plaintiffs, every conceivable measure of bias
> or intent suggests the WI plan is a strong outlier.  This includes a
> variety of tests that account for the state’s underlying political
> geography.  To my mind, this makes the Whitford case less a test of a
> particular standard or measure, and more a test of whether the court really
> wants to get involved in partisan gerrymandering in the first place.
>
> Eric McGhee
>
> From: law-election-bounces at department-lists.uci.edu<mailto:
> law-election-bounces at department-lists.uci.edu> [mailto:
> law-election-bounces at department-lists.uci.edu] On Behalf Of Michael
> McDonald
> Sent: Wednesday, June 14, 2017 4:12 PM
> To: Election Law Listserv <law-election at uci.edu><mailto:
> law-election at uci.edu>
> Subject: Re: [EL] Gerrymandering, the wasted votes / efficiency method,
> and geographic concentration
>
> The efficiency gap is a simple transformation of prior seats to votes
> partisan bias (gerrymandering detection) measures. If one party wins more
> than 50% of the seats with 50% of the vote, all measures will indicate that
> the party is favored in a redistricting plan. For this reason, the
> efficiency gap is no more or less challenged than other partisan bias
> measures and I suspect Justice Kennedy will find it wanting for a bright
> line that identifies when a constitutional violation has occurred, as he
> has done with every other measure presented before him.
>
> Simulations are problematic for another reason. Redistricting is such a
> complex graph partitioning problem that enumeration of all feasible
> redistricting plans is impossible in finite time. As a consequence, we
> cannot know the properties of any simulation algorithm that does not
> generate all feasible plans with equal probability. The only algorithm that
> is guaranteed to create plans with equal probability is one that randomly
> assigns blocks to districts and rejects resultant plans than are not legal.
> (This is similar to random sampling from a survey perspective.)
> Unfortunately, this algorithm produces feasible plans with exceedingly low
> frequency as to make it impossible to use in finite time. All other
> proposed simulation algorithms have never been proven that they can
> randomly sample. Indeed, we have shown that two proposed algorithms fail
> random sampling on a small toy example (see:
> https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2583528<
> https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2583528>). Failure to
> demonstrate the ability to randomly sample means that an algorithm could be
> biased in unknown ways, and might indicate the presence of a gerrymander
> when none exists, or fail to detect a gerrymander when one exists.
>
> The paper I link to describes the method of revealed preferences that the
> Florida and Wisconsin courts applied to determine a partisan gerrymander
> occurred. The method of revealed preferences simply looks at the adopted
> plans as they were developed and traces how partisan goals were elevated
> over traditional redistricting principles. In both cases, the courts waved
> legislative privilege to enable plaintiffs to see how the legislature
> incrementally traded off state constitutional or other traditional
> redistricting principles for partisan advantage through the course of
> generating test maps. In Florida, the efficiency gap was not put before the
> court in evidence, and simulations failed so spectacularly that the
> district court judge did not even bother to describe the evidence in his
> ruling. In Wisconsin, the court found a traditional partisan bias measure
> created by a consultant to the legislature was informative, as was the
> efficiency gap, in tracing out the legislature's preferences. I suspect
> that if Kennedy rules favorably for the Wisconsin plaintiffs, it will be on
> on the strength of the revealed preferences illuminated by applying both
> partisan bias measures to the test plans defendants produced in discovery,
> and not on the efficiency gap alone.
>
> ============
> Dr. Michael P. McDonald
> Associate Professor, University of Florida
> 352-273-2371
> www.electproject.org<http://www.electproject.org>
> @ElectProject
>
> On Wed, Jun 14, 2017 at 4:52 PM, Mark Scarberry <
> mark.scarberry at pepperdine.edu<mailto:mark.scarberry at pepperdine.edu>>
> wrote:
> My thanks to Bruce and to another list member who replied off-list. Has
> this point been made in any of the briefs?
>
> Mark
>
> Mark S. Scarberry
> Pepperdine University School of Law
> ________________________________
> From: Bruce E Cain <bcain at stanford.edu<mailto:bcain at stanford.edu>>
> Sent: Wednesday, June 14, 2017 1:43:49 PM
> To: Mark Scarberry; Election Law Listserv
> Subject: Re: [EL] Gerrymandering, the wasted votes / efficiency method,
> and geographic concentration
>
> Mark
>
> The efficiency gap is highly problematic for many reasons, and would be
> especially bogus for the reason you suggest if cross-sectional, over time
> data are used  rather than simulations, as is the case in Whitford…see
> Wendy Tam Cho’s web page or email her at <wendycho at illinois.edu<mailto:
> wendycho at illinois.edu>> for several forthcoming publications on this
> topic…
>
> B
>
> From: Mark Scarberry <mark.scarberry at pepperdine.edu<mailto:
> mark.scarberry at pepperdine.edu>>
> Date: Wednesday, June 14, 2017 at 1:30 PM
> To: Election Law Listserv <law-election at uci.edu<mailto:
> law-election at uci.edu>>
> Subject: [EL] Gerrymandering, the wasted votes / efficiency method, and
> geographic concentration
>
> I'm sure someone must have made the following point (if it is right).
>
> The wasted votes / efficiency method for measuring partisan gerrymandering
> would seem to take "one person one vote" to the next level. It would
> benefit parties (currently the Democratic party) whose supporters are
> geographically concentrated.
>
> Is that observation correct? Cites would be appreciated.
>
> Mark
>
> Mark S. Scarberry
> Pepperdine University School of Law
>
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-- 
Nicholas O. Stephanopoulos
Assistant Professor of Law
University of Chicago Law School
nsteph at uchicago.edu
(773) 702-4226
http://www.law.uchicago.edu/faculty/stephanopoulos
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