$25 million. That’s how much, prior to Osama bin Laden’s death in 2011, a hypothetical informant could have gotten for information leading to the whereabouts of the world’s most-wanted terrorist at the time. In the government’s story of bin Laden’s death, no one took that bait. In the controversial alternative version that journalist Seymour Hersh published recently—which the Obama administration vigorously disputes—the bounty was actually the key to bin Laden’s fate, the enticement for which a “former senior Pakistani intelligence officer betrayed the secret” of his whereabouts.

Whatever the truth, bounties like this one remain on offer for terrorists all over the world. Up to $25 million is available for “information that brings to justice” Ayman al-Zawahiri, bin Laden’s successor as leader of al-Qaeda. Zawahiri now tops the list of most-wanted terrorists sought under the State Department Bureau of Diplomatic Security’s Rewards for Justice program. Taliban chief Mullah Omar, Islamic State leader Abu Bakr al-Baghdadi, and Haqqani Network head Sirajuddin Haqqani occupy a lower tier—they’re worth up to $10 million apiece. Prior to recent unconfirmed reports of the death of ISIS’s purported second-in-command, Abu Alaa al-Afri, the State Department offered $7 million for information leading to his whereabouts. Some 46 terrorists are valued at $5 million each. And so on down to the relatively modest $1 million bounty for Radullan Sahiron, a leader of the Filipino terrorist organization Abu Sayyaf Group. It’s unclear whether a little-known ISIS official with the nom de guerre Abu Sayyaf (no relation), who was killed in a rare raid into Syria by U.S. Special Forces over the weekend, was on the list.

So just how are these numbers determined? Bounty amounts are based on the perceived threat a given terrorist poses to U.S. people or property, an official with the Bureau of Diplomatic Security told me. The secretary of state sets the price and can raise or lower it if, say, a terrorist gets promoted or demoted within an organization, or information emerges about planned attacks. If there’s a more precise formula, the official didn’t say.

The bureau’s explanation suggests the process is more art than science, but some believe bounties could be better priced. Alex Tabarrok, an economics professor at George Mason University, thinks the sums should be higher. In a post last week on Marginal Revolution, he noted that his research on bounties in the U.S. criminal-justice context had convinced him that bounty hunters are “an effective part of the American justice system.” But the bounty hunters he studied get paid to capture criminal defendants who have fled. “For international terrorists,” Tabarrok told me, “my thinking is mostly that these are for information acquisition—to tell us where [terrorists] are.” The ideal case is a terrorist insider who betrays the organization to get a reward. “So bin Laden, you know, kicks his cook one day, and the cook says, ‘I’ve had enough of this. Take this job and shove it.’”

But what influences the price at which this hypothetical cook will give up his boss? Is $25 million enough? In addition to factors like the risk a given terrorist poses to the United States, Tabarrok argued that the number should take into account the opportunity costs of pursuing strategies other than offering bounties. Calculating bounties this way would yield much higher amounts than current figures.

We could’ve put a bounty on bin Laden’s head in 2001 of, let’s say, $500 million. Instead we chose, no, we’re going to spend something like a trillion dollars invading Afghanistan, and then we’re going to be there for now over 10 years, and this is going to cost so many U.S. lives. Alex Tabarrok, economics professor, George Mason University

“We could’ve put a bounty on bin Laden’s head in 2001 of, let’s say, $500 million,” he said. “Instead we chose, no, we’re going to spend something like a trillion dollars invading Afghanistan, and then we’re going to be there for now over 10 years, and this is going to cost so many U.S. lives.” Of course, it’s impossible to know whether the offer of a higher bounty could have netted bin Laden right after the 9/11 attacks and thereby prevented the invasion of Afghanistan. According to the terms of the ultimatum that George W. Bush delivered to the Taliban in September 2001—“they will hand over the terrorists or they will share in their fate”—invasion wasn’t a foregone conclusion. By his own account, Robert Grenier, the CIA station chief in Islamabad at the time, was scrambling to forestall the invasion right up until the first American airstrikes started. In the counterfactual where an al-Qaeda insider betrayed bin Laden for money and the U.S. didn’t invade Afghanistan, Tabarrok said, “maybe $500 million doesn’t look so expensive” compared with what actually occurred.

But there are also costs associated with offers high enough to attract an overwhelming number of false leads. “We’d get a lot of tips that were totally off the wall,” Walter Deering, a former State Department official who oversaw Rewards for Justice, told The Washington Post’s Craig Whitlock in 2008. Tabarrok acknowledged that possibility, but noted that false leads are a cost of any kind of information-gathering operation—not least the the NSA’s bulk metadata collection program. “I actually think [the bounty program] is more targeted, so I suspect this is less of an information-overload program,” Tabarrok said. “You only pay a bounty when the guy’s actually captured … so there’s not really much of an incentive to offer useless information.”

Grenier, the CIA station chief in Pakistan from 1999 to 2002, who also led the CIA’s Counterterrorism Center before leaving the agency in 2006, told me he couldn’t recall a case from his experience in which a terrorist was apprehended as a direct result of a lead from the Rewards for Justice program. (The Rewards for Justice website lists Saddam Hussein’s sons Uday and Qusay Hussein, and 1993 World Trade Center bombing mastermind Ramzi Yousef, among its prominent success stories.) “I’m sure it’s happened but ... in my experience it just has not been a serious factor,” he said. “I certainly don’t know of any senior member of al-Qaeda who was ever brought in as a result of somebody who gave him up in hopes of getting monetary reward.” (Grenier was no longer with the agency by 2010, when Hersh claims the betrayal of bin Laden took place.)

Maybe the bounty prices were too low, but Grenier has heard an alternative theory. “Some of the speculation in the past has been ... that these are folks who can understand having a new Toyota Land Cruiser or 50 head of sheep, but $25 million is just like an abstraction, it doesn’t resonate with them. I don’t know if that’s true or not.” Scott Stewart, a former State Department official with the private intelligence firm Stratfor, has noted other reasons bounties may not work: First, “[m]ost of the people who are close enough to the target to provide actionable intelligence are in fact true believers and can't be bought.” Second, even if they could, they might not trust “the U.S. intention or capability to protect them or their extended families.”

Given all these factors, is it possible to find an ideal price point where the supply of terrorist-related information matches government demand for it? “I don’t know the optimal amount, but I’m pretty sure that we’re spending too little on these programs,” Tabarrok said. “Let’s keep raising it and find out.”