WASHINGTON — The CIA used an arsenal of severe interrogation techniques on al-Qaida prisoners for nearly seven years without ever seeking a rigorous assessment of whether the methods were effective or necessary, according to current and former U.S. officials familiar with the matter.

The failure to conduct a comprehensive examination occurred despite calls to do so as early as 2003. That year, the agency’s inspector general circulated drafts of a report that raised deep concerns about waterboarding and other methods, and recommended a study by outside experts on whether they worked.

That inspector general report described in broad terms the volume of intelligence that the interrogation program was producing, a point echoed in smaller studies later commissioned by then-CIA Director Porter J. Goss.

But neither the inspector general’s report nor the other audits examined the effectiveness of interrogation techniques in detail, or sought to scrutinize the assertions of CIA counterterrorism officials that so-called enhanced methods were essential to the program’s results. One report by a former government official — not an interrogation expert — was about 10 pages long and amounted to a glowing review of interrogation efforts.

“Nobody with expertise or experience in interrogation ever took a rigorous, systematic review of the various techniques — enhanced or otherwise — to see what resulted in the best information,” said a senior U.S. intelligence official involved in overseeing the interrogation program.

As a result, there was never a determination of “what you could do without the use of enhanced techniques,” said the official, who like others, described internal discussions on condition of anonymity.

Former George W. Bush administration officials said the failure to conduct such an examination was part of a broader reluctance to re-examine decisions made early after Sept. 11.

The Defense Department, Justice Department and CIA “all insisted on sticking with their original policies and were not open to revisiting them, even as the damage of these policies became apparent,” said John B. Bellinger III, who was legal adviser to former Secretary of State Condoleezza Rice, referring to burgeoning international outrage.

“We had gridlock,” Bellinger said, calling the failure to consider other approaches “the greatest tragedy of the Bush administration’s handling of detainee matters.”

The limited resources spent examining whether the interrogation measures worked were in stark contrast to the energy the CIA devoted to collecting memos declaring the program legal.

Justice Department memos released this month show that the CIA repeatedly sought new opinions on the legality of depriving prisoners of sleep for as long as seven days, throwing them against walls, forcing them into tiny boxes and subjecting them to the simulated drowning technique known as waterboarding.

How well those methods worked is facing independent scrutiny for the first time only now, three months after President Barack Obama banned the CIA from using them.

As part of an executive order shutting down the CIA’s secret prisons, the White House has set up a task force to examine the effectiveness of various interrogation approaches.

The Senate Intelligence Committee launched a similar review, and began combing through classified CIA cables that describe daily developments in the agency’s interrogations of al-Qaida prisoners.

“To the best of our knowledge, such a review has not been done before,” said a Senate aide involved in the probe.

CIA spokesman Paul Gimigliano declined to comment on the reviews, saying their contents remain classified.

A U.S. intelligence official who defended CIA interrogation practices said that, “Productivity was an obvious and important measure of the program’s effectiveness. The techniques themselves were not designed to elicit specific pieces of information, but to condition hardened terrorists to answer questions about al-Qaida’s plans and intentions.

“By that yardstick — the generation of reporting that was true and useful, that led even to other captures — it worked.”

Obama has described the agency’s activities as “a dark and painful chapter in our history,” and senior members of his administration, including Attorney General Eric H. Holder Jr., have called the techniques torture.

Defenders of the program, including former Vice President Dick Cheney, have accused Obama of dismantling a capability that was critical to keeping the country safe. Cheney also has called for the release of classified documents that he said will show how effective the program was.

Officials said that Cheney probably was referring to memos that were drafted by leaders of the CIA Counterterrorism Center to serve as talking points when the program was the subject of briefings to members of Congress and White House officials.

Many of those talking points have been cited publicly in recent years by senior government officials, starting with President Bush when he disclosed the CIA’s secret prison system in September 2006.

At the time, Bush said that “alternative” interrogation methods had been critical to getting al-Qaida operatives, including Abu Zubaydah and alleged Sept. 11 mastermind Khalid Sheikh Mohammed, to talk.

“I cannot describe the specific methods used,” Bush said. “But I can say the procedures were tough, and they were safe, and lawful and necessary.”

By then, Bush administration officials were concerned with a shifting legal landscape. Congress had passed new laws on the treatment of detainees, and the Supreme Court issued a ruling that undercut the Bush administration’s claim that al-Qaida prisoners were not entitled to the protections of the Geneva Conventions.

But officials said that the first high-level concern about the direction of the CIA’s interrogation program had come in 2003, when then-CIA Inspector General John L. Helgerson began distributing draft copies of his report on the program across the executive branch.

The document triggered alarms about waterboarding, documenting that it had been employed far more frequently — including 263 times against two al-Qaida prisoners — than widely understood.

The report also faulted how agency operatives applied the method, dumping large quantities of water on prisoners’ faces, apparently violating the agency manual and its agreements with the Justice Department. Nervous about the report’s implications, then-CIA Director George J. Tenet suspended the use of waterboarding in 2003.

The document also was critical of other approaches, including sleep deprivation. For all its criticism of the program, the 200-plus page document also included passages that have been cited by some as evidence that the interrogation operation was effective.

A May 2005 Justice Department memo noted that the inspector general’s report described an “increase in intelligence reports attributable to the use of enhanced techniques.”

A U.S. intelligence official familiar with its contents confirmed that the inspector general’s report contains language that is consistent with the assertions by former CIA Director Michael V. Hayden and others that the interrogation program accounted for more than half of the intelligence community’s reports on al-Qaida.

But officials said the document did not assess the quality of those reports. It also did not attempt to determine which methods were yielding the best information, or explore whether the agency’s understanding of al-Qaida would have suffered significantly without the use of coercive techniques.

“Certainly you got additional considerable volume of reporting when you started up with anything enhanced,” the U.S. intelligence official said. “But nobody went back to say exactly what were the conditions under which we learned that which was the most useful.”

In fact, Helgerson’s team had steered away from that question by design, the official said, hoping that agency leaders would turn to interrogation experts for a thorough study on which methods were working and which should be discarded.

White House National Security Council officials who saw the inspector general’s report became concerned with its conclusions, current and former officials said. Stephen Hadley, then the deputy national security adviser, was particularly persistent on pushing the CIA director to follow up on the inspector general’s recommendation.

Porter J. Goss, who had taken the helm at the CIA four months after the inspector general’s report was filed, eventually complied. But while Helgerson had envisioned a group of experts, perhaps including specialists from the FBI, Goss turned to two former government officials with little background in interrogation.

Gardner Peckham, who was a national security adviser to former GOP House Speaker Newt Gingrich, produced the approximately 10-page document that praised the program. It concluded that the program was “very structured and very disciplined,” said a former official familiar with its contents, but did not assess the effectiveness of various methods.

A separate report, submitted by John J. Hamre, a former deputy Defense secretary, was similar in scope and led to no significant alterations of the program. Hamre and Peckham both declined comment.

Despite the high-level attention, former Bush administration officials said they never saw the results of the audits that Goss had commissioned.

“They never came and presented anything to the White House that said in response to the I.G. report they have commissioned a review,” said a former Bush administration official. “They essentially came back with the recommendations that this was the program and it couldn’t be changed.”