Analysis of the Arizona Independent Redistricting Commission Congressional and Legislative District Maps

We have been retained by the Arizona Independent Redistricting Commission to analyze data from the congressional district maps drawn for the 2011 —2012 redistricting cycle and approved by the Commission. In this report, we estimate the extent of racially polarized voting, determine the identification and electability of the minority groups' candidates of choice, and (through a new method we introduce for the first time here) offer one way to evaluate whether stronger districts could have been drawn. We perform these analyses for both the benchmark map and proposed map, which allows for a judgment of whether the proposed map has a retrogressive effect. Our analyses are based on available quantitative information; much supplementary qualitative information will appear in other documents submitted by the Commission. We have conducted extensive analyses of this redistricting plan, with a large number of individual runs. The main body of this report explains the methodology (Section 2) and then gives the results (Section 3). The appendix gives more results, and our web appendix gives much more extensive and detailed results. Overall, we find that the two voting rights districts have similar levels of racially polarized voting between the baseline and new plans. On the basis of the quantitative information we have used, it seems straightforward to identify the candidate of choice of the Hispanic community and both new districts would seem to have the ability to elect these candidates. We also find that it would be difficult, and unnecessary if it were possible, to draw districts more favorable to minorities. We see no evidence of retrogression.