Minority members present alternate map and question partisan-symmetry testing and datasets

Representative Kamilla Owens and Senator Escamilla presented an alternate congressional map to the Redistricting Committee and said they retained an independent expert to test it. Owens said staff informed them the datasets used by the committee’s primary analyst would be made available; Owens said that dataset arrived the morning of the meeting and would be posted publicly.

Owens and Escamilla said they had hired Dr. Daniel Magleby, who described himself as an academic quantitative political scientist and said his analysis of the Owens–Escamilla map found it “consistent with what we would expect a neutral process to yield.” He said the map splits 13 municipalities and four counties and “falls well within the accepted range of what we would expect from a neutral redistricting process” when compared with standard simulation ensembles, including Harvard’s simulations.

Why it matters: Minority members raised procedural and methodological concerns about how the committee’s primary statistical tests were applied and whether the datasets used in those evaluations were the same across analyses. Representative Owens said she and Senator Escamilla had not been given full access earlier to the datasets they consider necessary to validate the symmetry and bias testing and that an independent expert should be able to review the data driving the committee analysis. Owens said, “We do have an expert with us who will be, who assisted us getting us to this map” and later that the dataset staff provided earlier that morning would be posted publicly.

Committee attorneys and other members explained the court-ordered constraints and the committee’s practice of drawing maps without using partisan voting data and then applying post-drawing tests to measure potential partisan impact. Mike Curtis of Lehi Research, identified himself during the meeting as counsel and summarized the statute as listing the seven Prop 4 criteria and also noting a “prohibition against purposefully or unduly favoring or disfavoring any incumbent, elected official, candidate or political party.” He read the statute citation as “section 28 19 1 0 3,” as enacted by Prop 4, and said the statute requires use of scientific methods, including measures of partisan symmetry, when evaluating maps.

Both sides said they had applied ensemble and quantile analyses; Dr. Magleby said he had requested the committee analyst’s data repeatedly and had not received it until the morning of the meeting. Representative Owens and Senator Escamilla said their independent analysis used Harvard simulation data and similar ensemble comparisons; they asked that all analytic inputs be made available so experts can independently verify the tests used to evaluate partisan impact. Committee leaders said some post hoc test results were available on the committee website and that committee staff had been asked to filter partisan material from committee-facing materials to avoid using partisan data in map creation.

Next steps: Committee staff said they will post datasets and supporting materials to the committee site; Owens and Escamilla said they would provide their expert’s analysis to the record as part of the public comment materials.