MANILA, Philippines?Former senator Francisco ?Kit? Tatad said on Wednesday that political surveys done by local pollsters have been ?fatally flawed? and based on methods long discarded by reputable polling firms in advanced countries like the United States.
?We are shocked that survey methodologies, techniques and practices that have failed and been completely discarded in the United States and other advanced countries are being used in local opinion surveys without any mention of their limitations,? he said, referring to polling firms like the Social Weather Stations and Pulse Asia.
?Thus, while claiming to serve the public interest, the surveys may have, in fact, only served some special political and commercial interests,? he said, reading from his report at the Fernandina Media Forum at Club Filipino in Greenhills, San Juan City.
Tatad also said the media had become ?unwitting purveyors of false findings to the detriment of the public and the electoral process.?
?Unsuspecting journalists have failed to ask the necessary questions that in the US and other countries are standard prior to publishing survey results,? he said.
The former senator cited the local pollsters' standard practice of face-to-face interviewing, a practice which he said has been considered inaccurate in the US following its failure to predict Harry Truman's victory over Thomas Dewey in the 1948 US presidential elections, as well as other erroneous forecasts after it.
Tatad cited a book by Kenneth Warren, ?In Defense of Public Opinion Polling,? which said that because of the sensitivity or personal nature of some questions, interviewers, in face-to-face situations, had admitted that they sometimes guessed or fudged responses.
?These methodological and practical problems, according to Warren, doomed face-to-face interviews forever. By 1980, nobody in the US wanted to pay for this type of 'fatally flawed and grossly inaccurate surveys,'? Tatad said.
Another weakness in local opinion polling, he said, has been the extensive and general use of ?quota sampling,? in which survey respondents were picked by age, sex, religion or income, as well as by various predetermined areas or region of the country, rural or urban.
Tatad said this was the most familiar form of ?non-probability sampling,?which was also found to lead to inaccurate results.
The senator quoted Warren's book: ?Quota sampling could never work in practice. Not only could pollsters not know the exact demographics so they could pick a representative sample that actually reflected the proper demographical proportions, but it was naïve to think that the interviewer could manage to interview the precise people needed to fill each quota.?
?Thus today, reputable US pollsters rely almost exclusively on probability random sampling to create a 'representative sample,'? Tatad said, quoting Warren.
Tatad said in probability sampling, ?every one of the 94 million Filipinos has a chance to be picked as a respondent.? In non-probability sampling, as practiced in the Philippines, the population is divided to certain categories, from which the respondents are picked, according to Tatad.
He also said the local opinion polling industry lacked professional standards.
?No law regulating the conduct of opinion polling, and no professional association of pollsters either to set and enforce standards of conduct and standards of disclosure and ensure 'the reliability and validity of survey results,'? Tatad said.
Tatad said he would invite one or two well-known US survey experts to critique local polling practices and to submit recommendations.
He called on the media to desist from giving further ?uncritical publicity to these dubious local polls and make an earnest effort on their own to correct or at least mitigate the harm already done.?
?We deplore the use of these questionable survey findings to condition the minds of the Filipino public and the media who have grown to trust opinion polls, largely because of hype,? Tatad said.
