They are not a blanket statement on the outcome, says psephologist

Rattling a box filled with 100 paper slips with the number seven or eight written on them, Rajeeva L Karandikar, a psephologist, asked a member of the audience to pick one.

The number turned out to be seven.

Displaying the sheet, he said: “In fact, 99 of the papers bear one number, with one slip being the exception.”

Now, tell me if it was seven or eight that constitutes the majority, he asked. The answer: You should not hazard a guess, and it would be imprudent to conclude it was seven because eight did stand a chance too. But one can be 99 per cent sure that the odd one out will be left out of the reckoning.

“This is what opinion polls are for you. They do not offer a blanket statement on the outcome, but can predict the public sentiment to a decent level of accuracy.”

Karandikar, Director, Chennai Mathematical Institute, has gauged public opinion for over 15 years now, publishing his polls across media, including The Hindu and the Network 18 group. He was speaking at a lecture on the science behind opinion polls at the Hindu Centre for Politics and Public Policy.

Sample size

In the backdrop of the demands to ban pre-election polls, he said the statistical model works, but agencies should be circumspect in their sample sizes and questionnaires to make sure the results are a reliable approximation of public sentiment.

Refraining to predict if it is a tightly contested constituency, including socio-economic profiles of voters, and carefully phrasing questions to avoid influencing, are some of the guidelines research agencies should follow. The media should demand that market research firms open up for an audit and disclose their field survey methods. “Instead of Government laying regulations, the media organisations may do it themselves,” he said.

Absolute accuracy in opinion polls in a country with an electorate of over 80 crore is near impossible. Over 21 lakh field enumerators may have to be fielded in the 543 constituencies, resulting in an expense of ₹100 crore, considering ₹500 for each field investigator.

“Such an expense, no one should do,” he said.

(This article was published on March 6, 2014)
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