Luis Mochán analyzed the overvotes and undervotes for those polling places that had sufficient data intact to do so, basing both totals and controls on the PREP. He used four different methods and came up with between 1.5 and 2.35 million overvotes and undervotes; these are calculated by comparing the number of votes plus the number of blank ballots remaining as reported in the PREP with sundry other numbers also taken from the PREP: the total number of voters signed in, the total number of ballots originally allotted to the polling place, and so on. Note that this vote count analysis is separate from his analysis of statistical anomalies in the PREP voting timeline. His September 7, 2006 paper (in English) discusses both of these analyses.