Marplots,
So the data gathered solely from news events? Do you think these curves will eventually be able to be used to plot traditional crime trends as well as terrorist-actions?
From what I read, they were commenting on a type of pattern (power law) common in nature and seen in human affairs as well. The first time I ran across it was in earthquakes -- the bigger the quake, the fewer.
It's interesting, but it isn't predictive, other than in the most general way. So, for instance, when they talk about an earthquake being 'due' they mean it in the same sense that a roulette player would say 'black is due' because there has been a long series of reds. In no way does it specify that any particular event will happen in any particular location, just that historically, the pattern emerges.
So, for instance, Tim McVeigh comes out of the woodwork and does his deed. The act could not have been predicted by a logarithmic relationship but it fits the curve we are talking about.
Because this is not valuable for prediction, historical data works fine. You could plot crime statistics as well from public records or even news reports.
The only important thing comes up when you can dig deeper into the mix and see if there is an underlying cause driving the rule. That's tougher. It is, however, just what we do with the stock market when we try to predict stock prices. We know there is a random element but we believe that enough information will allow us to pick winners. The difference with terrorism and the stock market is that in the latter, you only have to choose better than the other guy who is investing. In terrorism, you want to predict well enough to influence the outcome -- much harder.
If you think about the level of knowledge needed to predict and prevent a criminal act (and the very short time scales involved) you'd have to agree that the task is nearly impossible.
In my opinion, what works better than observation alone is getting your guys involved and pushing things along until you identify a propensity towards a criminal act. That means undercover folks and snitches mainly.
Although means and methods are often secret, I think you would find many preventative prosecutions are done exactly that way -- someone from law enforcement joins up and pushes the group toward a concrete act that can be charged.
I hope, somewhere in this screed, I've actually addressed your question.
Oh, and by the way, if you haven't yet checked it out: look at "Top Secret America" over at the Washington Post site. A whole network of government agencies and contractors busy as beavers on the hush-hush. Amazing, really.