[EL] “Flaws in the Efficiency Gap”

Mon Oct 2 17:14:03 PDT 2017

Engagement on the EG is always welcome, but these arguments either rehash points we’ve seen before or have little merit.  Taking them briefly in turn:

1.     The efficiency gap contains an implicit form of cost-benefit analysis; when made explicit, this form appears very peculiar and is hard to justify.

This claim is based on a scenario where one party wins all the votes in a state.  Beyond the implausibility of the scenario, it touches on issues that were first raised in my original peer-reviewed political science article three years ago. The practical effects are nil:  once a party has all the seats, it cannot draw a plan that hands itself more districts so there is no gerrymandering question to discuss. The alternative the authors propose (proportionality) would be a non-starter for the courts.  Moreover, it has conceptual problems of its own, some of which are identified in my forthcoming Election Law Journal article: http://online.liebertpub.com/doi/abs/10.1089/elj.2017.0453.

2.     The suggested threshold for congressional districts is scale-dependent, making it much easier to find gerrymandering in large states than in small states.

This is true, but has a very good justification: a seat is a seat from the perspective of control of the House of Representatives, so both the potential for and danger from gerrymandering are much greater in a state like California than in a state like Arkansas. At any rate, the threshold we propose is not central to the efficiency gap. If someone wanted to use a different threshold, or use percentages (or some combination), they would be free to do so. (And indeed Simon Jackman has done so in the ongoing North Carolina litigation.) The issue of percentages versus raw numbers is one that social scientists manage to work with all the time.

3.     The efficiency gap ignores whether voters are extreme or moderate, and instead identifies them only by their partisan labels. This can lead to polarization and can harm the supporters of the weaker party.

This point is purely speculative and at odds with the realities of modern American politics.  There is a mountain of evidence from political science (some covered in this paper http://online.liebertpub.com/doi/abs/10.1089/elj.2017.0452?src=recsys) that polarization is largely independent of district composition. This is because Democratic (Republican) legislators tend to be liberal (conservative) whether they are elected from safe or swing districts. Similarly, voters today rarely split their tickets and exhibit highly consistent behavior from election to election.

4.     The efficiency gap ignores uncertainty. (This has been noticed, to some extent, in the literature.)

This is simply false, as the authors themselves acknowledge.  Stephanopoulos and I proposed sensitivity testing to deal with uncertainty.  If Chambers, et al. find that unsatisfying, Simon Jackman has spent many pages of trial court reports empirically addressing the uncertainty and volatility of the EG, both ex ante and ex post. Moreover, the “volatility” of the EG is a feature, not a bug, because it ensures that all the uncertainty is on the table before a court intervenes.

In short, in my view this is largely old wine in new bottles.  To the extent that it is not, it is highly theoretical with only a limited understanding of the practicalities or relevant empirical literature.

Eric

Eric McGhee
Research Fellow

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________________________________
From: Law-election <law-election-bounces at department-lists.uci.edu> on behalf of Alan Miller <admiller at econ.haifa.ac.il>
Sent: Monday, October 2, 2017 2:41 PM
To: law-election at department-lists.uci.edu
Subject: [EL] “Flaws in the Efficiency Gap”

Hi everyone.

I just want to bring to your attention a new paper that I've co-authored with Chris Chambers and Joel Sobel. The paper examines the efficiency gap and identifies several aspects that we consider to be significant flaws. For the most part, our criticisms do not appear elsewhere in the literature that I've seen.

The paper is forthcoming in the Journal of Law and Politics, and the final version is available on SSRN: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3046797<https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3046797>.

To summarize our article in a few lines, we show that:

1. The efficiency gap contains an implicit form of cost-benefit analysis; when made explicit, this form appears very peculiar and is hard to justify.

2. The suggested threshold for congressional districts is scale-dependent, making it much easier to find gerrymandering in large states than in small states.

3. The efficiency gap ignores whether voters are extreme or moderate, and instead identifies them only by their partisan labels. This can lead to polarization and can harm the supporters of the weaker party.

4. The efficiency gap ignores uncertainty. (This has been noticed, to some extent, in the literature.)

I hope that those of you following this topic find the paper interesting, and am happy to both hear feedback and answer questions.

Best wishes,

Alan D. Miller

--

Faculty of Law and Department of Economics
University of Haifa, Mount Carmel, Haifa, 31905, Israel
admiller at econ.haifa.ac.il<mailto:admiller at econ.haifa.ac.il>; http://econ.haifa.ac.il/~admiller<http://econ.haifa.ac.il/~admiller>