A political earthquake shook California ten days ago when the Citizens Redistricting Commission released its first Congressional maps. Since their release, statisticians and pundits have been working furiously to figure out their consequences. Will the Democrats or the Republicans benefit? Which incumbents will be knocked off? How competitive will the new districts be?
Amidst all the excitement, no one has paid much attention to how well the commission actually did its job. The 2008 and 2010 voter initiatives that created the Commission require it to draw districts that are geographically compact, that preserve communities of interest and that protect minority voting rights. These requirements were at the heart of the heated campaign over the initiatives. Supporters argued that they would give rise to fairer districts, while opponents saw them as ambiguous and unenforceable.
So now that the commission has come up with its first maps, it's worth examining how well they comply with those controversial criteria. The answer, fortunately, is quite well, though there is still some room for improvement.
Starting with compactness, the new congressional districts score better than the existing districts along every quantitative metric. Their shapes are more circular, their boundaries are more regular and their perimeters are shorter. Some odd looking districts remain (for example, the dumbbell-looking district in LA's eastern suburbs) but they are noticeably rarer than before.
With regard to community preservation, the new districts also do a better job of keeping together various sorts of populations. On average, they are more homogeneous than their predecessors in just about every statistical category: income, education, occupation, housing, ethnicity, etc. This means that, as required by the initiatives, "population[s] which share common social and economic interests" generally have been kept whole rather than divided.
There are, however, a few districts that probably should be revised. For example, the new thirty-eighth district (the most heterogeneous in the state) combines Bel Air, Beverly Hills and other affluent areas with the gritty center of Hollywood. Similarly, the new forty-second joins the Westside with South LA, and the new twenty-fourth merges Oakland with the rich towns to its north. These districts (and a few others) may violate the initiative's community preservation requirement.
Lastly, the new districts are slightly better than the existing ones in the opportunities they provide to minority voters. There are currently nine districts in which Hispanics make up at least 40 percent of the citizen voting age population; this number rises to ten in the new plan. The number of analogous African American districts stays constant at one, while the number of analogous Asian American districts rises from zero to two. Still, different boundaries could have produced at least another couple districts with significant minority populations.
This analysis suggests that the commission did quite a good job in executing its mandate. It was charged with drawing districts that are aesthetically attractive, that coincide with communities of interest, and that treat minority voters fairly, and it did exactly that. This outcome vindicates the initiative's proponents and lends further support to the (already overwhelming) case for removing self-interested politicians from the redistricting process.
Still, there is no cause for complacency. The commission's plan, while promising, can and should be improved over the next few months. In particular, some of the LA-area districts probably should be revised so that they correspond better to underlying communities. With some edits of this sort, California can complete what is already a dramatic turnaround: from poster boy for gerrymandering in the last decade to model of fair redistricting in this one.