The poll field work, oversight and analysis was conducted and provided by the Mexico City-based office of Ipsos-Bimsa, an international polling firm. Ipsos-Bimsa currently operates in 64 countries worldwide and is certified by the European Society for Opinion and Marketing Research. 

The population under study was residents of the state of Oaxaca, men and women 18 years and older and registered to vote.

The poll was conducted using a multistage probability sample.  Geographical areas were identified using information from the National Institute of Statistics and Geography of Mexico.  Each geographic area was then randomized through a probabilistic sampling proportional to its size.  Conglomerates of blocks within each geographical area were randomly selected and within each conglomerate households were selected using a method of systematic sampling where an address is randomly selected as a starting point and then the k-th continuous residence to the previously selected household is polled next, where k is the number obtained by dividing the total number of households in the conglomerate by the size of the sample required in that conglomerate.

Respondents were selected based on their being registered to vote and producing a voting card that confirmed their address as the one where the interview was taking place.  If more than one person at the address met those criteria, the respondent was selected using the Kish Method. 

A sample of 820 face-to-face interviews were conducted between August 23-29, 2008. 

The margin of error is +/- 3.5 points at 95 percent confidence level.

Demographic Breakdown