Applying FixCache to Code Inspections

Rahman et al. have used a fixcache/bugcache approach to predicting which files should be singled out for code inspection. I have written about using a similair approach for regression test selection (here and here). Their main conclusion is:

When used for inspection, FixCache gets most of its
power by predicting that les that recently experienced
a bug x, do in fact contain additional, latent bugs.

So basically, what they have found is that bugs tend to occur grouped in the same file. I guess there is some profound truth here. But is this just some kind of random statistical property of software artefacts or does it tell us something fundamental about software development?

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