After action review
An after action review (AAR) is a structured review or de-brief process for analyzing what happened, why it happened, and how it can be done better, by the participants and those responsible for the project or event. After-action reviews in the formal sense were originally developed by the U.S. Army although less structured de-briefs after events have existed since time immemorial. Formal AARs are used by all US military services and by many other non-US organizations. Their use has extended to business as a knowledge management tool and a way to build a culture of accountability.
An AAR occurs within a cycle of establishing the leader's intent, planning, preparation, action and review. An AAR is distinct from a de-brief in that it begins with a clear comparison of intended vs. actual results achieved. An AAR is distinct from a post-mortem in its tight focus on participant's own action - learning from the review is taken forward by the participants. Recommendations for others are not produced. AARs in larger operations can be cascaded in order to keep each level of the organization focused on its own performance within a particular event or project.
Formal AAR meetings are normally run by a facilitator, and can be chronological reviews or tightly focused on a few key issues selected by the team leader. Short cycle informal AARs are typically run by the team leader or assistant and are very quick.
After action reviews in the military 
There are basically two types of military AARs—formal and informal. Formal AARs require more detailed planning, preparation, and resources. They are normally scheduled and conducted as a part of external and internal evaluations. Informal AARs require less planning and preparation than formal AARs and are often on-the-spot reviews of soldier and collective training performance at crew, squad, or platoon level.
Formal AARs are normally conducted at company level and above. However, when a training event is focused at squad or platoon level, and resources are available, a formal AAR may be conducted to gain maximum training benefit. Externally evaluated lane training, small-unit ARTEPs, and tank and BFV gunnery tables are prime examples. Informal crew, squad, and platoon AARs are held prior to company and higher-echelon AARs.
The AAR facilitator (evaluator or controller) provides a mission and task overview and leads a discussion of events and activities that focuses on the objectives. The discussion with leaders and soldiers should orient on the use of terrain integration of key BOS ([Department of the Army Publications 1] Battlefield Operating Systems), and leader actions. The discussion should also examine the weapons systems and doctrine used by the enemy during the exercise. At the close, the AAR leader summarizes comments from the observers, covering strengths and weaknesses discussed during the AAR and what the unit needs to do to fix the weaknesses.
Informal AARs are usually conducted for soldier and crew-, squad-, and platoon-level training or when resources are not available to conduct a formal review. They are often held for lower echelons prior to a formal company- or higher-level AAR, though they may be conducted at company level. Informal AARs are extremely important since they involve all soldiers and leaders in the participating unit. The formal company AARs for the training event depend on these thorough, informal reviews. These are sometimes referred to as a hotwash.
Informal AARs are conducted similar to formal AARs and may be done for large or small units. They may be scheduled, or leaders may do on-the-spot reviews during the training. Discussion comments could be recorded to use in follow-on AARs or to apply immediately the lessons learned as the exercise is repeated.
To apply this tool ask yourself and the team 
- What was planned?
- What actually occurred? (facts not judgments)
- What went well and why?
- What can be improved and how?
See also 
- Mosley, Troy. "Operational Terms and Graphics". FM 101-5-1. Department of the Army. Retrieved 6 February 2013.