the same tendencies. The explanation of this alleged 'anomaly' turned out to be both easy and forceful: the fundamental variable that explains the collection of information in the PREP is the distance between the polling place and the district council (plus how slowly or quickly the polling place itself tallies the votes), while in the district councils the count advances as a function of the speed with which the tally sheets are confronted by the councils themselves, the discussion that takes place in them, and whether or not the electoral packets are opened." José Woldenberg was a founding member of the Unified Socialist Party of Mexico (PSUM, 1981), the Mexican Socialist Party (PMS, 1987) and the PRD, which he left in April 1991. He was president of the IFE from 1996 to 2003 and oversaw the 2000 general election. Allegations of added or missing votes (overvotes and undervotes) On July 10, 2006, Frontera NorteSur, reporting on an initial analysis by Civic Alliance, wrote: "In the Lopez Obrador strongholds, 312,450 more votes for senators than president were tallied, while in the pro-Calderon zones, 403,740 more votes for president than senators were tabulated." However, they do not specify which candidate seems to benefit from this. For example, in the PAN stronghold of Guanajuato, both candidates received almost exactly the same number of votes above their corresponding senatorial candidate, with López Obrador edging Calderón by 51,498 to 51,283 The Civic Alliance claimed that in some Calderón strongholds the number of votes cast greatly exceeded the number of registered voters. Pliego Carrasco, however, (see analysis below) found that the totals were similar for polling places carried by López Obrador. López Obrador also claimed that there were 1,621,187 votes added or missing from 72,197 polling stations (55.33% of total number nationwide). See article and chart with breakdown of numbers: It also has links in the sidebar to various scientific studies on the presidential election results. 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