Tuesday, November 22, 2011

Should statistics change people’s minds?

Source: http://dailyinfographic.com/face-off-occupy-wall-street-vs-tea-party-infographic

A friend of mine just had a breast cancer scare. Given where the mass was in her body, people kept reassuring her that she had only a 25% chance of malignancy. Her response was always the same: “You are telling me that I have a one-in-four chance of getting cancer. These are NOT good odds!”


Thankfully, the masses turned out benign, but her point was well taken. One-in-four is not ideal when we're talking about cancer. The problem is, statistics don’t tell us anything about a specific case. If it is true that one in ten people are homosexual, it is not necessarily true that I have four homosexual students in my forty-person class. I could have none, ten, or even forty. Statistics only talk about patterns. Yes, they show how likely it was that she had cancer, but they didn’t tell her whether or not she did (the most important fact). Only the medical tests do that.

Patterns do inform us about things. Take the above chart. Despite the generally agreed-upon caricature, seventy percent of Occupy Wall Street protestors are currently employed, but only fifty-six percent of Tea Party members are. Also in comparison, the largest number of Occupy protestors was 1.4 million; the largest tea party protest was 300,000. It looks like many more people support the former than the latter, yet the latter has much more political clout in the United States.

In essence, what this chart shows is that the stories the media are telling about the Occupy movement are largely inaccurate. The question before us, then, is: should these facts change anyone’s mind about the Occupy movement? People in it are employed, educated, and more than half of respondents  agree with their goals (I don’t know the details of the survey, so I'm not clear on what "agree with" means). Ought this persuade naysayers to take another look?

There is a logical fallacy called “appeal to the people” that points out that just because most people agree with something doesn’t make it true or right; consider slavery or the oppression of women. Logic teachers have been telling their students for ages not to take popular opinion as fact. Yet, at the same time, surely we should consider community opinion when we deliberate about controversial issues. Popular opinion can help balance out our subjective attitudes. Society can and does teach us things.

So, where does this leave us? When faced with statistics that give us a different understanding of something, are we obligated to change our mind, or can the numbers be dismissed because they don’t offer certain information? Given how much polls have already been cited in the American presidential election, I can think of no better time to start trying to focus on this question.

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