Majority-minority districs and congressional elections

The other day in our research group we discussed a recent paper by Delia Grigg and Jonathan Katz (Social Sciences, Caltech) on majority-minority districts and Congressional elections. Jeronimo presented the paper, and David Epstein and I discussed it. This was a lively discussion, partly because Jonathan’s conclusions disagreed with the findings of David’s work on majority-minority redistricting (for example, this paper with Cameron and O’Halloran). In fact, scanning David’s online C.V., he appears to have a paper with Sharyn O’Halloran from 2000 entitled, “The Impact of Majority-Minority Districts on Congressional Elections,” which is the exact same title as Grigg and Katz’s paper!

The Grigg and Katz paper had two main conclusions: first, that majority-minority districts (MMDs) increase minority representation, and second, that there is no evidence that MMDs help the Republicans. According to David, the first claim is in agreement with what all others have found, so we focused on the second claim, which would seem to contradict David’s earlier study that found MMDs helping the Republicans.

This is (or has been) a big deal in redistricting in the U.S.: is it appropriate to carve out districts with mostly minority population, in order to increase the representation of ethnic minorities in the legislature? Will such rediscticting, paradoxically, help the Republicans (a party supported by only a small proportion of ethnic minority voters in the U.S.)?

I don’t have any recent data easily at hand, but here’s some representation data from 1989 (reproduced in this 2002 paper in Chance):

Proportion of

Proportion of seats in House
U.S. population of Representatives
Catholic 28% 27%
Methodist 4% 14%
Jewish 2% 7%
Black 12% 9%
Female 51% 6%
Under 25 37% 0

Major comments

On to Grigg and Katz . . . their paper has some data on individual districts but focuses on analyses with state-years as units, comparing states with no minority-majority districts to states that have at least one majority-minority district. Our main comment was that these comparisons will be difficult, for two reasons:

1. States with majority-minority districts are much different than states without. For one thing, states without MMD’s are much smaller (this can be seen in Figure 3 of Griggs and Katz; the discreteness of the “no MMD” proportions imply that these are states with few congressional districts.

If we are imagining MMD’s to be a “treatment” and are interested in the effect of MMD’s, then we want to compare comparable states that do and don’t have MMD’s. Keeping all 50 states in the analysis might not make sense, since many states just don’t have a chance of getting MMD’s.

2. We were wondering if it would be helpful to look at the number of MMD’s in a state. We could imagine that a state would necessarily have 1 or 2 MMD’s, just from geography, but then redistricters could have the option to increase that to 3 or 4. In this case, we’d want to compare numbers, not just 0 vs. 1-or-more.

Other comments

Grigg and Katz used a parametric-form seats-votes curve (from King and Browning, 1987) to estimate partisan bias and electoral responsiveness in groups of state elections. I suspect they’d get much more precise and informative results using the newer JudgeIt approach (see here for a description and derivation).

To confirm things, I’d suggest that Griggs and Katz fit their models, using as outcome the Republican share of seats in the state. This is cruder than partisan bias but might show some general patterns, and it’s less subject to criticisms of their parametric seats-votes model.

I liked how they presented their data and results using graphs. But we had a couple of questions. First, what are those “no MMD” points on the far right of Figure 14? We were wondering which was the state that was 35% minority, with minority Congressional seat shares around 40%, but no majority-minority districts. We were also confused about the tables on page 27 because we couldn’t get the numbers to add up.

In summary . . .

The Grigg and Katz paper is an innovative look at majority-minority districting, following an approach of looking at the whole state rather than one district at a time. This is an approach Gary King and I have liked in studying redistricting in other contexts. However, I am not sure what to make of Grigg and Katz’s substantive conclusions, because I don’t know that their comparisons of states are appropriate for this observational study, and I worry about their measure of partisan bias. I hope these comments are helpful in their revision of this paper, and I thank Jonathan for sharing the paper with us.

P.S. Some people find political redistricting, or race-based redistricting, distasteful. By evaluating these programs, we are not making any moral judgment one way or another. Rather, we’re trying to answer some empirical questions that could be relevant for considering such plans in the political process.

4 thoughts on “Majority-minority districs and congressional elections

  1. Uh…what's the point of the table entry (Under 25, 37%, 0)? Isn't this an artifact of the constitution, rather than apportionment?

  2. Mike,

    The point of all of the table entries is that there are a variety of sources of mismatch between the demographics of the U.S. and of Congress. The different groups were chosen to give a sense of the scale of things. Not intended to indicate anything directly about apportionment. The underrepresentation of women certainly can't be directly due to apportionment either.

  3. Grigg and Katz were clearly motivated to debunk the idea that there are perverse consequences associated with redistricting, namely benefiting Republicans (it doesn't get more perverse than that!). The last line of their abstract is:

    The claim that majority-minority

    districting has “perverse-effects” is not supported by the data. So it's a good bet that their research was politically motivated. They set out to find and massage data to support a foregone conclusion.

    I can't get too excited about the redistricting issue, since the largest inequity in the Senate is the whopping 46% underrrepresentation of women. Unlike race or religion, this has nothing to do with how districts are drawn.

    To me, the interesting question is this:

    There are 100 senators. It is logically impossible for every group to be "fairly represented" where actual frequency equals observed frequency because there are more than 100 groups:

    men

    women

    blacks

    Methodists

    left-handed people

    gay people

    Jews

    pagans

    Buddhists

    vegans

    etc.

    So it's silly to do an analysis like this without first asking what types of equity we care about. Given all the flavors of Christianity, it seems ridiculous to have Methodist on the list.

    Gender equity is probably the most important, with some sort of racial variable next (historically oppressed vs. historically not opporessed). Religious diversity is important, but the categories should be jewish, christian, muslim, buddhist and maybe others. Not Methodist, Catholic, etc.

    Surely there are women out there just as competent at decision making as Strom Thurmond or Rick Santorum.

  4. Deb,

    I don't know the political motivations underlying the Griggs and Katz work, but just about everything in political science has some political motivation (of course). Just because someone's work has political relevance (and thus a potential political motivation), it doesn't mean that they "set out to find and massage data to support a foregone conclusion." I work hard to ensure, to the best of my abilities, to never do this. And in my work with Jonathan Katz, I've never seen him set out to massage data, etc.

    Regarding your other comments–yes, a more systematic study would be good. We gathered the data on Methodists, etc., just to have some comparison groups in a study we did 10 years ago comparing representation of blacks and whites. Looking at Methodists and Catholics is not completely ridiculous given that Methodists have traditionally been considered a mainstream denomination whereas Catholics have traditionally been considered to be outsiders in mainstream U.S. culture. I think it's too strong for you to say "the categories should be . . ." There are lots of ways to study representation, and no reason not to look at Methodists etc. and see what's happening.

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