Snyder et al on Malapportionment

"Left Shift," chapter from upcoming book with Ansolabehere
"Equal Votes, Equal Money: Court-Ordered Redistricting and Public Expenditures in the American States," Ansolabehere, Gerber, and Snyder, APSR, Dec 2002

These two papers assess the impact of court-ordered redistricting on state politics in the US. In the ten years following the landmark Baker vs. Carr decision of 1962, all US states redrew their congressional district boundaries to more closely approximate a "one-man, one-vote" rule. Malapportionment had become rampant in many states, with (at the extreme) a voter in a rural county in California having 400 times the voting power of a resident of Los Angeles. This had come about because levels of representation remained fixed while county populations changed, often drastically. It is easy to imagine that this would happen through neglect and inertia, but of course any system of representation creates a constituency that opposes change.

Both papers assess the impact of the Warren Court's judicial intervention, but they differ in the effect they are looking for. The 2002 APSR paper examines the change in intra-state transfers (primarily state education distributions to the counties), which would be expected to change because more even representation across counties should lead to more even spending. "Left Shift" looks at changes in the level of state spending (such as the total expenditures on welfare and education), which would be expected to change if the more strongly represented counties preferred a different level of spending. Both papers manage to recover the effect theory would lead us to expect. (In both cases the authors state that previous work had failed to find these effects.)

The APSR paper appears to be mainly a product of data collection -- the production of county level data on population, representation, spending, and demographics for both before and after the redistricting. The demographic data is of particular interest because it seems likely that other factors at least partly explain the changes in transfers they document. For example, perhaps the districts that gained representation also received more transfers because predominantly black counties had been underrepresented and blacks were also granted expanded social services in the wake of desegregation. Perhaps it was these other reforms directly benefiting blacks, rather than electoral reforms giving them more representation, that explain the increased spending on these counties. The authors address this by including "percent black" among their demographic variables, and relate that it does not affect their results: they say there is not a statistically significant interaction term between changes in malapportionment and percent black (presumably as measured in the 1960s) in a regression predicting county-level changes in spending. For me, this was not quite reassuring enough (considering that this would be the leading counterexplanation for their findings), but fairly convincing and surprising.

"Left Shift" takes on a complementary problem: did changes in representation lead to changes in policy? The prediction at the time of these reforms was apparently that state governments would adopt more liberal policies once the power of rural districts were curtailed, and Snyder and Ansolabehere report that previous work had not found this correlation. Their approach is to dig into the survey data to look at the changes in public opinion (as represented in the statehouse) that would result from reapportionment. What they find (using a variety of surveys) is that only in a subset of states did opinion vary geographically in the way the liberal advocates of reapportionment thought. In the Northeast, the Great Lakes states, and the coastal West (essentially, the future blue states), the overrepresented rural areas were more conservative and more likely to favor small government than the underrepresented cities and suburbs. In the rest of the country, the differences were smaller; in the South, suburban voters were among the most conservative. The effect of redressing urban/rural electoral imbalances on social spending is thus expected to vary from region to region. Indeed, Ansolabehere and Snyder report, policy did get more liberal in the "Left Shift" states and not in the remainder.

Here, the potential for confounding is large and not really addressed. The Left Shift states are essentially the blue states, as I mentioned above, and my impression was that there has been a divergence in political preferences on national politics between blue and red states. Blue state/red state polarization in national politics is something which clearly cannot be attributed to changes in the structure of representation in state legislatures. Perhaps political preferences in the blue states are diverging from those in the red states, perhaps due to economic conditions, geographic sorting, changes in the party platforms, or the political rise of the Christian right. If so, "Left Shift" can not get a good estimate of the effect of redistricting on state spending: the treatment is perfectly confounded, as they say in the causal effects literature.

Overall, I find these papers to be admirable in their marshaling of lots of interesting data that is appropriate to the hypotheses they want to assess. The strengths and weaknesses of the papers are an outgrowth of the policy intervention they study. The strength is that the units (states) did not choose to implement this reform, which alleviates a host of confounding problems. On the other hand, redistricting had no control group. (In "Left Shift" the authors try to argue that the non-Left Shift states are a control group in the sense that the policy should not affect them, but it is clear that there may be other confounding factors that applied differently to the treatment and control groups, rendering the estimation muddled.) What is admirable is the relative cleanness of the estimation, considering the substantive importance of the questions they examine.