petitioned the U.S. Supreme Court to grant ... - Election Law Blog

27aAppendix Dlevel method and the BG level method, he believes that thetract level method has higher statistical reliability. (PL’sEx. 1, at 7.) The tract level method estimates citizenshiprates for the block level by applying data from the tractlevel to block level. (Trial Tr. vol. 1, 72-73, Feb. 17.) Dr.Rives, however, criticized the tract level method on thegrounds that it relies on the assumption that the blockswithin the tract are homogenous with respect to the ratesof citizenship. In his opinion, heavily Hispanic areas ofthe City tend to have lower rates of citizenship. (Defs.’Ex. 4, at 12-13.)Dr. Rives advocated the application of the BG levelmethod. He asserted that because BGs are smaller thantracts, they are more likely to emulate the demographicfeatures of the blocks they contain. Also, the BG levelmethod may be more precise because BGs are smaller,and it is therefore easier to closely approximate the actualarea included in the illustrative district. However, Mr. Elycritiqued the BG level method because in formulating aspecial tabulation for Hispanic citizenship rates at theBG level, the Census Bureau relies on two independentlyrounded numbers in order to preserve participantconfidentiality, thus decreasing accuracy. (PL’s Ex. 4, at 1.)Also, the smaller sampling size at the BG level increasesthe likelihood of sampling error. (Id. at 2.)In his initial expert report, Mr. Ely constructedillustrative districts using citizenship information from thetract level. (PL’s Ex. 1, at 7.) Applying this methodologyto 2006 ACS data, Mr. Ely drew the original IllustrativeDistrict (July 7, 2008). (PL’s Ex. 1 and 3.) As discussedabove, Mr. Ely then extrapolated growth rates in order