The expected utility of drone strikes


A recent article in The Economist asks whether US drone strikes in Pakistan help or hinder the war on terror. A friend of mine explained to me why he thought they did more harm than good. Suppose a drone strike takes out two Al Qaeda operatives, he said, but causes several civilian casualties too. The outrage caused by this collateral damage will inflame anti-US sentiment in Pakistan, and some of that sentiment will translate into support for Al Qaeda.  Some of that support will further translate into some people actually joining Al Qaeda.  Even if only 0.1% of Pakistanis are sufficiently outraged by the drone strike to support Al Qaeda, and only 0.1% of them will actually join the organization, that is still 170 new recruits (since Pakistan has a population of 170 million).  So the net gain for Al Qaeda is 168 terrorists (170 new recruits minus 2 casualties).

Of course, the precise figures will depend in part on the ratio of terrorists killed to civilian casualties, and there is some disagreement about this.  In his excellent book, Task Force Black, the BBC journalist Mark Urban claims that “most of the people killed in these attacks are innocent bystanders” (p.xiv, Foreword to Paperback Edition,2011). But The New America Foundation, a Washington think-tank, estimates that 80% of the 2,551 people killed in drone strikes since 2004 were militants, rising to an astonishing 95% in 2010. The expected utility of drone strikes could depend crucially on who is right.

Even if the drone strikes mainly kill militants, their utility may also depend on whether these are terrorist chiefs or low-level fighters. According to the New America Foundation, out of the 2,551 deaths, only 35 were recognized militant chiefs, or just 1.3% of the total. Among these high-level hits was the fearsome leader of the Pakistani Taliban, Baitullah Mehsud, who was the country’s number one public enemy. Nevertheless, the vast majority of targets have been low-level fighters.

There are also disagreements about local perceptions.  While those in Islamabad might react with anger, many locals privately support the strikes against extremists who have overrun their homeland.  What may inflame anti-US sentiment more than the civilian casualties in themselves, however, may be the lack of transparency and accountability. There is no investigation of civilian casualties, and no compensation paid, and some question the legal basis of the attacks.

It is probably too early to be sure whether the drone strikes are harming al-Qaeda and related groups, or spurring on Afghanistan’s powerful insurgency.  But my friend’s argument does at least set out the terms in which we should be thinking about this question, and suggest the kinds of data we need to collect before we can reach a definitive verdict.  How, for example, can we measure anti-US sentiment? And what objective metrics might we use to judge overall success?  One such metric might be the number of suicide attacks in Afghanistan.  Unfortunately, on this measure, the drone strikes do not appear to be achieving their aim; over the past year, the number of suicide attacks in Afghanistan, many launched from Pakistan, has soared.