Strategy Page has an excellent short article on how the “lessons learned” in battle are used (and sometimes abused):

American operations in Afghanistan and Iraq brought out the military historians and survey teams in force. The Department of Defense was determined to avoid the usual wartime pattern and not make the same mistakes twice during the War on Terror. This is not easy to do. As far back as World War II, there were organizations in the U.S. military that looked for “lessons learned” and tried to get the information passed around to everyone as quickly as possible. This was difficult because the training all the troops (be they army, navy or air force) received was laid down in manuals and training courses. It was exceedingly difficult to change training manuals, if only because of the time required to rewrite them and publish new ones. The training courses were based on the manuals and the military, like any bureaucracy, lives to do things “by the book.”

Although the image of military leaders always preparing to fight “the last war” is deeply embedded in popular culture, it isn’t universally true. Some leaders certainly do think and act as if the next battle will be much like the last one. Others go too far the other way and seem to feel that the next battle will have nothing in common with the last one. Neither extreme is accurate for most military leaders (at least in western armies).

Most generals don’t actually command troops in the field — in effect, they’re uniformed managers, directors, and other bureaucratic functionaries — and those generals will be the ones most likely to expect tomorrow to be a clone of today. Bureaucracies operate best when “business as usual” is the pattern. Generals in the field don’t have that luxury.

It’s easier to identify a lesson than to get an organization to act on it and implement a useful solution. For that reason, the British like to use the phrase “lessons identified” to make clear that just noting a problem does not solve it. When you uncover a problem, you are calling into question the wisdom of some earlier decisions. Large organizations do not take kindly to such criticism. Excuses and creative explanations will emerge if a lesson learned threatens some cherished program. For example, before the invasion of Iraq, the attitude in the Department of Defense was that heavy forces (tanks and all their accompanying armored vehicles) were on their way out. But what led the dash to Baghdad? Tanks. Embedded journalists made it pretty obvious how useful the tanks and other armored vehicles were. The Department of Defense had a hard time absorbing this lesson. Another example occurred when many helicopter gunships got shot up when they flew, according to current doctrine, deep into enemy territory to attack Iraqi tanks and troops. This “lesson learned” has sparked a major debate in the army aviation community, for billions have been spent to build an attack helicopter force that can “go deep.” Now that it’s been tried on a real battlefield, and failed, painful decisions are called for. Such decisions may not be made. It’s happened before.

Getting the right equipment in the hands of the troops in the field is very important, but how the troops use those tools matters at least as much. A classic example of this is the differences between the French and British armoured formations in the early part of World War Two and their German opponents. The allied tanks were at least as good as the German tanks, but the way they were used wasted almost all of their strong points. The early German tanks were not designed for tank-to-tank slugging matches: they were just good enough to engage enemy tanks. The task of killing enemy tanks fell to the German anti-tank forces, who were used much more aggressively than their French or British counterparts.

The British cavalry units (equipped with faster, more lightly armoured tanks) were used like Napoleonic cavalry, charging forward to engage German tanks (and their usually hidden-from-sight anti-tank units). In most cases, the British tanks would be decimated in the process, but didn’t realize it wasn’t the Panzers doing the damage.

British leadership took the wrong lesson from the experience, and as late as the fall of 1944, were still using medium tanks like the Earl of Cardigan’s Light Brigade, and still losing them in droves. The British tanks had improved, but their doctrine was still faulty, and many soldiers died as a result.

In a more modern vein, even leaders on the same side can take very different interpretations from the same experiences:

But there are other problems as well. “Lessons learned” often become twisted to support pet projects. The air force has, since 1991, come up with quite different “lessons learned”, than the army, for the very same battles. Air force doctrine sees air power becoming the dominant combat force, while the army sees the primacy of ground forces unchanged. The air force also has a hard time accepting the fact that in Afghanistan and Iraq, their contribution was to have aircraft circling overhead, dropping smart bombs at the command of army troops down below. Air force “lessons learned” play up the traditional air force use of complex combat missions, using highly trained pilots and expensive electronic equipment. The air force does not want to dwell on the valuable contribution of their heavy bombers acting as delivery trucks for smart bombs ordered by combat troops.

I’m sometimes amused that it was always the aristocratic cavalry looking down on the lowly peasant infantry and the bourgeoisie in charge of them. The classes have faded in importance, but it was cavalry officers who took to flying in WW1, and now it’s the aristocratic air force looking down on the peasant army. Patterns repeat.

Afghanistan forced everyone to take a closer look at Afghan history, which revealed some interesting local customs (tribalism, corruption and the great honor bestowed on those who take loot.) But Afghan history also reveals an acceptance of change, a desire to get away from the constant warfare and blood feuds, and the willingness of traditionalists and warlords to resist those changes. Another lesson re-learned was one the British noted over a century ago; “you can’t hustle the East.”

Normally, no one really wants a totally dispassionate look at the lessons learned. No one wants the chips to fall where they may. Too much collateral damage that way. Yet, in the end, truth and logic will rule. The true meaning of each lesson learned will be there on the next battlefield, whether you have come up with the best implementation of the lesson or not. In wartime, the lessons identified are quickly followed by learning and solutions. In peacetime, you can put off the reckoning. But not when an enemy is trying to kill you, and failure to react to lessons identified and learned can get you killed.