MEXICO CITY—Recent polls show that Mexico's presidential contest is tightening, with most showing only a few percentage points separating the main candidates three months ahead of the July 2 vote.
But the polls have set off a fiery debate about their reliability and whether Mexico's pollsters are too closely aligned with the campaigns.
All the polls show that Andres Manuel Lopez Obrador, the former Mexico City mayor and candidate of the Party of Democratic Revolution (PRD), has slipped in popularity, compared with his two main rivals, Felipe Calderon of the National Action Party (PAN) and Roberto Madrazo of the Institutional Revolutionary Party (PRI).
One poll, by the Economists Group and Associates and Applied Social Research, even suggested that Calderon had surpassed Lopez Obrador, who's led the national polls for more than two years.
But few believe that to be true, and most political analysts say they believe Lopez Obrador is still leading, though Calderon is closing the gap.
Political analyst Jorge Chabat, a researcher at the Center of Investigation and Economic Instruction in Mexico City, said he thinks Lopez Obrador probably remains ahead of Calderon by five percentage points.
Political polling in Mexico is a relatively new phenomenon. Until the late 1980s, the country's electoral politics were the exclusive domain of the PRI, which, in addition to controlling all the politicians, controlled the labor unions, television stations and most newspapers. Most businesses also were aligned with the PRI.
Then in the early 1980s, opposition parties began to win local and state offices and the PRI took to using polls to measure its waning support.
The real impetus for polling here, however, was the dramatic 1994 presidential election. With an armed rebellion in Mexico's southern jungles and the assassination of the PRI candidate, the nascent Federal Election Institute brought in international observers and solicited polls to lend legitimacy to the process.
"We have a mature industry—it has grown a lot," said pollster Ulises Beltran, who got his start measuring public opinion for the PRI.
Polling in Mexico differs from its U.S. cousin. For one, it's relatively more expensive because Mexicans aren't as likely as U.S. residents to have telephones. That means pollsters in rural areas must go door to door.
For another, Mexican political loyalties are in flux, making it difficult to count on party loyalty to help predict voter behavior.
The PRI, for example, has lost many loyalists over the last several years. Even the PAN, whose candidate, Vicente Fox, won the presidential election in 2000, can't count on previous supporters. About 30 percent of the voters who supported Fox in 2000 plan to vote for Lopez Obrador, said Francisco Abundis, director of marketing and opinion research firm Parametria.
Finally, Mexican pollsters don't ordinarily include undecided voters among their results, leaving it largely unknown how many voters are still available to be persuaded by one candidate or another.
In a poll done for the Mexico City newspaper Milenio, pollster Maria de las Heras showed Lopez Obrador with 34 percent of the vote, Calderon and Madrazo polling 31 percent and other minor candidates accounting for 4 percent. But the poll made no mention of the 18 percent who de las Heras found were undecided.
Pollsters say they don't include the undecideds because they assume that those people won't vote. But Chabat notes that the campaigns still are battling for their loyalty.
"There is still some vote to fight for," said Chabat.
For many here, of course, the polls are highly suspect and subject to political manipulation.
Lopez Obrador quickly denounced the most recent polls showing him slipping as part of a campaign against him. Calderon continued to attack the long-running lead candidate, hoping to continue the trend. Madrazo took out an optimistic ad graphing his support out to 35 percent on Election Day.
De las Heras' background as a PRI party pollster was an issue when her poll was released last week.
Of course, just as in the United States, the polls can vary wildly. Even as a survey by the Economists Group and Associates and Applied Social Research taken March 18-21, put Calderon ahead of Lopez Obrador 36-34, a survey by Consulta Mitofsky taken at more or less the same time gave Lopez Obrador a seven-point lead.
Following are the results of recent polls.
CONSULTA MITOFSKY (March 17-23)
Lopez Obrador, 37.5 Calderon, 30.6 Madrazo, 28.8, Other, 3.1
ECONOMISTS GROUP & ASSOC./APPLIED SOCIAL STUDIES (March 18-21)
Lopez Obrador, 34, Calderon, 36, Madrazo, 28, Other, 2
BELTRAN AND ASSOCIATES (March 24-27)
Lopez Obrador, 36, Calderon, 34, Madrazo, 28, Other, 2
MARIA DE LA HERAS (March 30-April 3)
Lopez Obrador, 34, Calderon, 31, Madrazo, 31, Other, 4
(c) 2006, Knight Ridder/Tribune Information Services.
ARCHIVE PHOTOS on KRT Direct (from KRT Photo Service, 202-383-6099): Calderon, Lopez Obrador, Madrazo
ARCHIVE GRAPHICS on KRT Direct (from KRT Graphics, 202-383-6064):
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