BBC article on cycling accidents

Well, the general idea is that patterns can only be observed in large samples. If we're talking about 8 fatalities and 7 of those are women, or are wearing blue shoes, or are called Sheila, then the PD says that that can't be extrapolated out to a larger sample, and therefore be the basis of any probabilistic claims, because randomness clusters. It's what it does. So you say that it can't be down to chance: well, it could be.

My point is that 8 HGV fatalities is not the sample, it's a set of observations from a larger sample, or pair of populations, men and women cyclists, where the available observations are 'Died by HGV this year' or 'Did not die by HGV this year'. Clustering doesn't come into it.