<p><pre><code>    I&#x27;m not sure what you are getting at with your school example.
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It&#x27;s quite simple. Clearly there are times to consider the individual and clearly there are times when we should consider larger groups.<p>If Town A had a cancer rate 5 times higher than the national average surely you wouldn&#x27;t say, &quot;Well, look, those people are individuals, and an individual&#x27;s cancer risk is affected by lots of things -- diet, exercise, genetic predisposition... to heck with looking for differences between Town A and Town B.&quot;<p><i>Clearly</i> you&#x27;d want to start investigating things that affect Town A on a town-wide basis.