Companies repeat mistakes for two reasons: They never identify what went wrong, or, if they do diagnose a problem, they don't institutionalize the solution. Often, managers limit their postmortems to asking for three things that went well and three things that went badly and then initiating a round of applause for Michael, who was here all night making the presentation binders.

Some businesses take a more regimented approach, adopting a practice from the military. The U.S. Army is famous for its rigorous debriefings, known as after-action reviews, or AARs. To borrow the Army's definition, an AAR is "a professional discussion of an event, focused on performance standards, that enables soldiers to discover for themselves what happened, why it happened, and how to sustain strengths and improve on weaknesses."

Charles Parry, a partner at Signet Research & Consulting who teaches after-action reviewing to corporate clients, prefers the term action review cycle. That's because the process wraps around an entire "action," which might be as simple as a client meeting or as elaborate as a yearlong business-development project. "There's a piece you do ahead of time called the before-action review, or BAR," explains Parry. "That's where you ask the question 'What is our intended result?' When the action is over, you ask 'How did we do against that?' "

Formal AARs are rare in smaller companies, which prize informality. But they are gaining traction in a few self-styled "learning organizations" -- like Moody, Famiglietti & Andronico, a 100-employee accounting and consulting firm in Tewksbury, Massachusetts. MFA is big on continuous improvement: It employs a full-time education director and devotes one week each summer to classes on customer service, negotiations, and similar subjects. (The company once held a dining-etiquette session at a Holiday Inn.) After reading about AARs four years ago, MFA's leaders decided to bake them into every customer engagement, no matter how small. "AARs and BARs -- they're famous here now," says Matthew Boyle, an MFA partner. "When an e-mail goes around saying 'There's a BAR on Client X,' everyone knows exactly what to expect."

What they expect is a 15-to-30-minute, hyperefficient meeting that includes every person who has interacted with the client within the past year. Also attending are employees with experience in similar projects for different clients. Before the meeting, the presiding partner distributes a prep packet that includes the client's tax and audit information. BARs are not the place to get up to speed. You show up up to speed.

MFA offers many services, each provided by a different, highly specialized team. BARs allow those specialists to share information, anecdotes, and impressions about clients so that everyone knows everything. At a BAR held prior to a tax assignment, for example, someone from wealth management might describe the client's aversion to talk of succession planning. The meeting participants identify facts the tax team will need to know and questions the client will probably ask. And they discuss what results will give this client the greatest satisfaction. "We come out knowing what we know, what we don't know, and where we should seek to have the biggest impact on their business," says William Andronico, also an MFA partner. (Parry points out that at most small companies, this kind of conversation "is a few people talking in the car on the way to the client's office.")

Over the course of the project, the tax team members will meet several times for a quick tire kick. Each time, they will ask, Has anything changed? Have we learned anything that should alter our strategy? If a best practice emerges during these meetings -- say, someone created an electronic template for collecting information that works better than the paper version -- the team shoots an e-mail about it to the rest of the firm.

To keep memories whole and impressions fresh, MFA tries to hold AARs within a day or two of a project's completion. The first question at an AAR: How do you think it went? "Everybody interprets things differently, so it's important to get subjectivity out of the way and have everyone agree on what happened," says Boyle.

The group next compares results with intentions formed at the BAR. Did the accounting firm save the client as much money as expected? If not, why not, and how can those mistakes be avoided? If something the firm did saved the client more, what practices can be enshrined for future jobs? The group also hashes over softer lessons: This client's CFO never makes a decision unilaterally, so make sure to copy the CEO on questions that need swift resolution. Never schedule meetings at the client's office, because there will be constant interruptions. Notes from the AAR go into the company's CRM software for when the client calls again.

One result of the AARs and BARs is that clients see those at MFA not just as accountants but as well-rounded businesspeople, says Andronico. Nothing falls through the cracks as clients move from one service to the next, and performance improves with each new gig. "In the old days, when there were just 30 of us, everybody pretty much heard everything," says Andronico. "But as you grow, you need a venue to pass on experiences, good and bad."

In addition, employees work harder to detect flaws and concoct fixes, because their ideas will live on long after the project has ended. "With action review cycles, people know they'll have to sit in a room with their peers and focus, with rigor, on whether things are working," says Parry. "And they know that the system will be listening."