Statistical Science

The 2004 Venezuelan Presidential Recall Referendum: Discrepancies Between Two Exit Polls and Official Results

Raquel Prado and Bruno Sansó

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We present a simulation-based study in which the results of two major exit polls conducted during the recall referendum that took place in Venezuela on August 15, 2004, are compared to the official results of the Venezuelan National Electoral Council “Consejo Nacional Electoral” (CNE). The two exit polls considered here were conducted independently by Súmate, a nongovernmental organization, and Primero Justicia, a political party. We find significant discrepancies between the exit poll data and the official CNE results in about 60% of the voting centers that were sampled in these polls. We show that discrepancies between exit polls and official results are not due to a biased selection of the voting centers or to problems related to the size of the samples taken at each center. We found discrepancies in all the states where the polls were conducted. We do not have enough information on the exit poll data to determine whether the observed discrepancies are the consequence of systematic biases in the selection of the people interviewed by the pollsters around the country. Neither do we have information to study the possibility of a high number of false or nonrespondents. We have limited data suggesting that the discrepancies are not due to a drastic change in the voting patterns that occurred after the exit polls were conducted. We notice that the two exit polls were done independently and had few centers in common, yet their overall results were very similar.

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Statist. Sci., Volume 26, Number 4 (2011), 517-527.

First available in Project Euclid: 28 February 2012

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Exit poll data Venezuelan recall referendum


Prado, Raquel; Sansó, Bruno. The 2004 Venezuelan Presidential Recall Referendum: Discrepancies Between Two Exit Polls and Official Results. Statist. Sci. 26 (2011), no. 4, 517--527. doi:10.1214/09-STS295.

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  • Collier, R. (2004). Venezuelan politics suit Bay Area talents: Locals help build Chavez’s image, provide polling data. San Francisco Chronicle, August 21, 2004.
  • DeGroot, M. H. and Schervish, M. J. (2002). Probability and Statistics, 3rd ed. Addison-Wesley, Reading, MA.
  • Delfino, G. and Salas, G. (2011). Analysis of the 2004 Venezuela referendum: The official results versus the petition signatures. Statist. Sci. 26 479–501.
  • Hausmann, R. and Rigobón, R. (2004). In search of the black swan: Analysis of the statistical evidence of fraud in Venezuela. Technical report, John F. Kennedy School of Government, Harvard Univ.
  • Súmate (2004). Preliminary report: The presidential recall referendum.
  • Taylor, J. (2007). Too many ties? An empirical analysis of the Venezuelan recall referendum. Technical report. Dept. Statistics, Stanford Univ.
  • The Carter Center (2004). Audit of the results of the presidential recall referendum. Final report.
  • The Carter Center (2005). Observing the Venezuela presidential recall referendum.