lower frequency, higher impact

So if you’re an insurgent group under pressure to the extent that you can’t stage attacks with the same frequency, what to do? Go for a smaller number of bigger bangs, maybe.

The 2nd Brigade, 3rd Infantry Division calls itself the "Send Me" brigade, and on Saturday, its soldiers were quick to send themselves to find the man who shot Pfc. William L. Edwards, a wide-eyed 23-year-old from Houston. They quickly identified the house where they believed the assailant was hiding and moved in, just as the sniper knew they would.

Inside the house, one soldier stepped on a pressure plate, detonating an estimated 30 pounds of explosives hidden under a stairwell. In an instant, four troops were killed; four others were injured. Edwards died later in the hospital. The sniper escaped.

…ambushes and rigged houses can cause many more casualties than smaller improvised explosive devices, which rarely kill more than one or two people at a time. Increasingly, Donnelly said, insurgents are creating a "daisy chain" of house bombs, in which an initial explosion can trigger blasts up and down a block.

House-borne IEDs is apparently the official term. See also the tanker bomb attacks the other day. I suppose you could, if you were a true believer in “the surge” argue that…

suicide bombers simultaneously detonating four fuel-laden trucks in two villages in north-western Iraq

…and killing upwards of 250 people is actually a measure of success. Good luck with that one.

UPDATE: On the other hand, maybe not such lower frequency after all:

The supply of IEDs and the men to deliver them has become so plentiful that there has been a decline of what is known in the narcotics trade as "street value." In 2005, the teams emplacing IEDs were being paid $100 for each successful blast. Now in central Iraq the payoff is sometimes as low as $40.

Comments

[Justin]

"We study the enemy, and we have a basic idea of how he uses these houses and how he plants initiators," Lynch said. "As their tactics evolve, ours evolve."

Sounds like driving cattle through a minefield.

This evolving is done via testing to destruction, obviously. In any evolutionary system there are always those who fail to make the leap forward. The fish who failed process oxygen on land, the GI who stood on a pressure plate etc. etc.