[mattraibert]

I read it that way at first too. But if you read a little further, the article centers on providing evidence for the model. Specifically he shows evidence that a a state with higher G has linearly higher D (which is exactly what the model states).

[aszepieniec]

And then when the evidence does not match up, he fudges with one of his parameters, V, to "explain" it.

[mattraibert]

This seems like a non-sequitur. The gp's criticism was that the article doesn't cite any evidence for the model, which he does.

Besides, he doesn't "fudge" V. He shows evidence: that violent crime decreased over the relevant period and argues that less violent crime implies lower average tendency to violence (V).