So even before all the candidates were nominated, submitted nominations were reviewed/accepted/rejected the Clairvoyants Pollsters of CNN-IBN would like us to believe they can show us the light, never mind all previous attempts that lead us into the ditch of electoral outcomes.
Yesterday Offstumped questioned what was new about CNN-IBN’s methodology, well today we take a shot at dissecting that methodology which is described here.
So first off CNN-IBN throws a 3 letter word at us -PPS to explain why its selection of Assembly Constituencies at random is representative.
So what is PPS ?
This paper from a South African University has a good primer on Sampling and Sampling Design. The bottomline is when CNN-IBN picked the 75 assembly seats for the survey from a total of 224 it did so by giving smaller constituencies a higher weightage of being selected when compared to bigger constituencies so that when ultimately sampled there is no bias based on size on who gets selected to participate in the survey.
So you have 75 constituencies big and small, now what ?
CNN-IBN selected 4 polling booths from each using a different technique called “systematic random sampling”, never mind the oxymoron that is a technical term. The same paper above explains this technique as well. In summary its just a way of picking x number of people at fixed intervals starting with a randomly determined start point. There is a problem with this approach which the paper explains as most lists may have a bias in which they are organized.
So the 4 polling booths picked by CNN-IBN may not be as random as we imagine them to be.
Now to pick the actual participants in the survey the same technique was used to selected 30 voters from the updated voter lists after delimitation. Once again as explained above there maybe a bias in this selection as the technique suffers from any bias the list may have in terms of how entries are organized.
CNN-IBN further says that of the 9000 they picked based on the above only 5124 responded. Which means that close to 50% of the randomly picked participants did not participate in the survey.
So what we have here is a survey with only around 50% of a representative sample set with all its flaws based on the techniques described above.
Now we all know in India that there is usually a bias to who participates in an Opinion Survey and who doesnt. So despite CNN-IBN’s tall claims that the 5124 sample set matches the demographic in the state in terms of gender and religion and caste it by no means indicates their socio-economic status.
So there is no basis for CNN-IBN to have even come out with this survey in the first place for its sample set is defective and suffers a bias which is obvious from the non-participation in the survey.
Offstumped Bottomline: Unless CNN-IBN can prove that the sample sub-set that did not participate in the survey is similar to the sub-set that did it on the basis of socio-economic status, ideological bias and past voting history, there is no way it can claim on the basis of gender, religion and caste that its sample set is representative and that its prognostication for the outcome of polls in Karnataka is credible.? CNN-IBN must apologize to the people of Karnataka and withdraw its opinion poll.
Filed under: Karnataka Polls 2008
[...] Offstumped Bottomline: Unless CNN-IBN can prove that the sample sub-set that did not participate in the survey is similar to the sub-set that did it on the basis of socio-economic status, ideological bias and past voting history, there is no way it can claim on the basis of gender, religion and caste that its sample set is representative and that its prognostication for the outcome of polls in Karnataka is credible. CNN-IBN must apologize to the people of Karnataka and withdraw its opinion poll. [...]
Rajdeep and Yogendra Yadav should be tried and should be sent to jail if it is proved that they have tried to alter the perception of the electorate…
There should be some law to check these surveys which have gross malafide intentions…..
Although the flaws you have mentioned are perfectly valid and indeed these loopholes can be used for propaganda, but all statistical processes have some loopholes. Basically statistics and psephologist try to review a small sample set and extrapolate it to a wider electorate; thus making their predictions.
Another point that i would like to mention is that to understand how mass media reacts, you have to understand why it was formed in the first place. In post after post, you say they are biased and tell how they are anti center of right and distort the facts.
Though i agree with all your posts, mass media was never meant to be a savior of the people. Newspapers and news channels have been used for various propaganda whether by the Britishers in India or the freedom fighters(before independence), and post independence primarily by the congress.
So any form of mass media, will always have a certain amount of bias. I hope there was better and a fairer way in which opinion polls could be conducted, but till they are too dependent on ‘mass media’, nothing better than their present quality can be expected.
they have taken lot of pains to make a servey it very good to have servey be it parlament or assembly there are more than five candidates for each seat i am sure it is congress way no one wanted 20/20 what has happened is shame on nation what b j p done by accepting 20:20 , it has lost all popularity it has got before and joined the power mongers party lost all glory it has in minds of people of karnataka had it got election after dharam singh no doubt it is b j p by joing with baap /beta party it has invited its troble any way history can not be rewriten let the servey be correct and save katnataka
jai karnaraka matha
CNN-IBN is a joke especially Mr. Sardesai and Yadav. Their bias is no longer hidden, nor does it have any effect on the Indian electorate.
Most of us are practical, right conservative people. Without the caste and religious divisions, left, centre-left would have been wiped out decades ago.
[...] « Karnataka Polls – Dissecting CNN-IBN’s Survey Methodology [...]
http://ibnlive.com/news/as-karnataka-set-for-poll-muslims-say-they-feel-unsafe/64458-3.html
http://ibnlive.com/news/as-karnataka-set-for-poll-muslims-say-they-feel-unsafe/64458-3.html
Another gem from CNN-IBN. An article which has zero content as to why muslims are feeling scared or who is scaring them. If you watch the video, there is a shot of a BJP ad asking how terrorists have reached south india. I have no idea at all how it is relevant to the discussion.
anonymous…Concur with you, I just saw it, looks a like a Congress ploy……
Yossarin,
Get over it. It’s only an opinion poll, which are dime a dozen during election time. Your own UP poll predictions are still fresh in memory. You can claim you are no psephologist in your favor, but that didn’t stop you from doing the predicitons.
jujung,
It’s not just an opinion poll, it’s an attempt by the media to influence the outcome of an election. Considering how successful they were in Gujarat, one would assume Sir-desai would have learnt his lesson, but like an obedient puppy he’s just responding the to cues of his pack leader, a special breed of Italian maltese =)
Guys…It is not strange … I used to follow the so called Yogender when he was working with DD … He is the worst political analyst, i have ever seen…. He never act at least with common sense…
Just an Ex:
I closely followed this channel CNN-IBN on Gujarat counting day… Even when the numbers were half crossing, Yogender said BJP can not cross 90+… I still remember, he showing his number and comparing the actual numbers… It clearly shows the difference… even a 5th Standard math kid can tell the difference and yogender cant…
I doubt if he really knows statistics and prediction theories…
5000 people in 70 constituencies project to around 13 Million peoples verdit and 212 Constituencies!!…Is he doing probability analysis or statistic analysis… i doubt…
Rajdeep is more a clown…disgraceful for being a high end journalist and manipulating things. Indian Government (Congress Govt) awarded Padmabushan for his .. ….. ??
The values of political survies and the media values in our country had gone a long time back…
I have lost all respect for Rajdeep and Yogendra. I know that they are biased towards one party, butI din’t know that Rajdeep would stoop to this level.Even though I do not belong to any political party, being in Karnataka,I know the ground reality. I’m sure, CNN IBN would be made to to apologise to the people of Karnataka on 25th May. In the process, they are going to lose viewers too…
[...] Sandeep, so where is the CNN-IBN’s Yogendra Yadav - Will he rise to the challenge and defend his prognostication against global benchmarks or concede and quit [...]
[...] will be on the line here. Offstumped will be particularly interested to see if Mr. Yadav will defend his initial prognostication and if so what rationale he will [...]