So, Republicans have been getting 8-10% more votes in larger districts than in smaller ones in Arizona -- that's proof? Only in wishful thinking of "progressives".
Not only in Arizona, no. He started his research in Arizona, and eventually learned that this is happening across the country. Obviously you did not RTFA (Or not well). And there should be no correlation between district size and voting results. For example, large cities often have a mix of large and small voting districts that are right next to each other, with very similar demographics.