It sounded so authoritative, when a top Obama administration official claimed this week that the U.S. killed roughly 10,000 enemy fighters in its fight with the self-proclaimed Islamic State. Until that figure was contradicted by a second official. And then undercut by a third.

Not only could Obama administration officials not agree on the final death toll, they could not say how they determined such a figure with no ground forces in Iraq and Syria to assess airstrike damage. Nor could those officials articulate how well such a statistic measures progress against the terror army.

By the end of the week, many administration officials were admitting a defeat of sorts. They conceded that it was foolish to talk openly about body counts in the first place, when dead fighters are such an irrelevant measure of the conflict.

“The killed in action and other activities should only be measured in how much those deaths affect ISIS’s capability to conduct operations, how it affects its maneuvering, its logistics, its command and control, or impinge its effectiveness to maintain the initiative and conduct operations,” said retired Army Lieutenant Colonel Derek Harvey, who testified last month before the Senate Armed Services Committee about the U.S. strategy.

Or as an adviser to the U.S. military on its campaign against ISIS explained to The Daily Beast: “These are the types of numbers that novices apply.”

Antony Blinken, the deputy Secretary of State, is no novice, however. He’s a career diplomat and policymaker with decades of experience. Yet he still said in a speech in Paris that the U.S.-led coalition campaign had killed 10,000 ISIS fighters. On the same day, General Herbert “Hawk” Carlisle, commander of Air Combat Command, told a group of reporters that 13,000 ISIS fighters had been killed. And on Friday, Air Force Lieutenant General John W. Hesterman III, Combined Forces Air Component commander, said “at least” 1,000 ISIS fighters had been killed each month, or at least 9,000 members of the terror army.

You’d think with all the pseudo-precision about the numbers of “KIAs,” or killed in action, that the U.S. military would keep track of how many enemies it wounds. Two Pentagon officials tell The Daily Beast that this isn’t the case.

Conservatively, experts said that if 10,000 ISIS fighters were indeed killed, at least 20,000 could be wounded. If those estimates are roughly correct, that would mean 30,000 ISIS fighters have been injured or sent to their deaths.

According to intelligence community estimates, there are somewhere between 21,500 and 31,000 ISIS fighters on the battlefield.

With that, the numbers left officials scrambling to explain how nearly every ISIS fighter could potentially be wounded or killed—and yet so potent. By midweek, some Pentagon officials said that they believe ISIS is able to replace every dead fighter with a fresh one.

And in a briefing with reporters Thursday, Army Colonel Steven Warren, a Pentagon spokesman, said the deaths had led ISIS to force men—including teenage men—to join the ranks. If true, that would suggest the air campaign is potentially killing teenagers, the Pentagon had to concede.

Still other officials maintained that the deaths were a strain on ISIS’s combat ability—even as the terror army has claimed in the last month the Iraqi city of Ramadi and the Syrian city of Palmyra, marking two of the group’s biggest claims.

“Make no mistake: Our coalition team is having a profound effect on the enemy, ” Hesterman said.

The question over numbers led to a growing debate about the value of such numbers. While some Pentagon officials said they were only one metric of the war, other officials kept on citing them.

“They don’t understand the enemy and they can’t make any real judgments about impact. And you have people like Blinken who don’t understand the kind of fight we’re in,” the adviser said. “It’s self-defeating to get into this [numbers] game.”

(Blinken, for his part, defended using the numbers in an interview with CNN, saying: “This was in the larger context” of recent territorial gains by ISIS.)

There is no standard measure for counting enemy deaths from airstrikes. While many strikes are captured by video and troops can count the number of fighters at a strike site, there is no way to confirm those figures. And in instances where the number is not clear, the military often uses a high estimate. For example, if a U.S. strike destroys a moving Humvee, military officials will count four deaths even though there could potentially be just one person in the Humvee.

Moreover, when airmen provide damage assessments after a strike, they often offer varying degrees of confidence, from low to high. There is no standard for what level of confidence warrants counting an ISIS death.

Most important, with no troops on the ground there is no way to accurately assess battlefield damage, defense officials conceded. When asked Friday how the U.S. military tallied such a figure, Hesterman refused to offer one, replying only, “conservatively.”

“I do think there is an element of the theater of the absurd here. The Pentagon is generating killed in action numbers as if we had an accurate count. There is no way to do that, unless you have boots on the ground doing the counting,” said Christopher Harmer, senior naval analyst with the Middle East Security Project for the Washington, D.C.-based Institute for the Study of War.

This week, top defense officials publicly sought to mitigate the number’s value. Privately, many said the lessons from Iraq and Afghanistan—wars in which officials once boasted of killing al Qaeda and Taliban fighters—is to not use those numbers. The estimates don’t really measure a terror’s group grip on a country.

Progress is “not measured in terms of casualties produced, but rather in terms of disruption to command and control, disruption to their ability to resupply themselves. If you recall, when we started the campaign they [ISIS fighters] were moving with relative impunity across both eastern Syria and western Iraq. And they certainly can’t move with impunity now because they’re targeted. And so they are disrupted, both in terms of their ability to command and control, to resupply themselves,” Army General Martin Dempsey, the chairman of the Joint Chiefs of Staff, told The Washington Post this week. “But they’ve also demonstrated a certain resiliency and the ability to recruit, in particular with a significant skill that they display in the social media.”

But the KIA figures—and the Pentagon explanations of them afterward—suggested that the airstrike campaign was far from defeating ISIS. At best, the attacks were maintaining the status quo. And by saying ISIS deaths hurt the group, the U.S. undermined its own creditability, Harmer said.

“The longer the U.S. keeps pushing the demonstrably false narrative that ISIS is in disarray and retreat,” he said, “the less credibility we are going to have with the moderate rebels in Syria who are ostensibly our boots on the ground there.”