Conflicting Polls

Last week I posted some polling from Jorge Buendía that suggested that the PRI's summer cakewalk was not a foregone conclusion: the PRI enjoyed voter preference of 41 percent, the PAN 38 percent, the PRD 17. Today, El Universal released numbers that were disheartening for the PAN: if the elections were today, 40 percent of the electorate would punch its vote for the PRI, against 25 for the PAN and 14 for the PRI. Obviously, there wasn't a 12-point swing in just a couple of days, so there must have been some fundamental discrepancies in sample or phrasing of the question that caused the wider margins this time around. The only question is which of the two is closer to reality? Thus far, the majority of polls seem to be closer to Buendía's findings than the El Universal poll, although conventional wisdom supports the prediction of a PRI whitewash.