Scott & Sarah Kennedy

Friday, August 26, 2005


Michelle posted an excellent comment with info about polls. So I thought I would post it so you can all read it easily. Anyway here it is....(hope you don't mind Michelle)

Aah Scotty, but here is something the News Media will not tell you...
Opinion polls should be taken with a grain of salt and are very unrelible. (except that the public belives them and thus votes accordingly)
I am learning about this in my Political Behaviour and Psychology class at Uni. Basically there are many problems with opinion polls, here simplified into

a) margin of error. The poll that you linked to does not say directly what the margin of error is, which is bad reporting, but it does mention numbers which denotes (the 1000 respondents) about a margin of error of 4 percent. That is actually quite large. And means that Labor may be anywhere from 41-49 (never never use decimal points in polls, also sign of a bad poll) and National may be between 32-40 percent. This could make the popularity of the two parties much closer. A possible one percent!

b) A sample of 1000 people (which this poll is) is about a middle-sized sample, and still cannot accurately guage public opinion. For example, if they conducted a phone survey, what about people without phones? (those either too poor to afford it, or those who wish to remain unlisted) The poll mentions Aucklanders, and thus had a specific focus on those in the Auckland region (as many polls do).

c) Additionally, in opinion polls people often change their answers to impress the interviewer (probably not applicable in this case), or they are pushed into boxes that they dont actually fit into. For example, if the question says "are you more likely to vote National after their tax cut announcement? yes or no , then opinions are actually being created for people who were not intending to vote National anyway.

And one last little gripe about this opinion poll... 10 percent of respondents (it says 9.6, but as i've said, never use decimal places in polls, its pointless and simply used to try and show something thats not there) (eg. Labour is on 45.3 [45%] and National is on 36 [still 36%] makes it look like Labour is further ahead)
sorry - distracted =)
10 percent of respondents were "undecided, refused to say, or did not know". Thats quite a large percent!!

Anyhoo, hope that gives you a bit of insight into why opinion polls aren't very reliable and you shouldn't be influenced by them (even though the majority of the population are, which is why the media and politicians use them)


By michelle, at 11:18 AM


  • And just to add -
    My boyfriend was pointing out all the holes in my argument and came up with this "tell me of a poll that has not accurately predicted an election"....
    The problem is that the general public believes the polls, and votes accordingly. For example, if it looks like National is down 13% on Labour, then some National supporters will decide that its not worth it, and wont vote. For other people, seeing Labour's popularity will change their minds and they will decide to vote labour (seeing as its so popular).

    so yeah. Stick to your guns!! read about parties and find out for yourself... don't just vote on what everyone else is doing, or what the polls say =)

    (thanks for posting this, Scotty... i feel famous!

    By Anonymous Michelle, at 2:03 PM, August 27, 2005  

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