The Planning Exercise: The Complete Guide

If you ask any British Army officer, past or present, what their most uncomfortable moment at Main Board was, you are likely to get the same answer. The Plan Ex grilling. I still remember mine like it was yesterday, though it was actually over eight years ago. The looks of disapproval from the DS every time I answered a question, and the feeling of being completely out of my depth.

I didn't know it at the time, but this is how almost every candidate feels. The planning exercise is designed to do this, because the DS wants to see how you respond when you are put on the back foot and forced to make decisions when you feel like you have no idea what's going on. They want to know whether you will rise to the challenge or whether you will fold. After all, you may have to do this for real, with soldiers looking back at you rather than colonels with clipboards.

In this guide I will break the assessment down in full. The format at both Briefing and Main Board, the four phases every planning exercise follows, and the mistakes that you must avoid.

What Is the Planning Exercise?

The planning exercise, usually shortened to the Plan Ex, is an assessment you sit at both Briefing and Main Board. You are given a dense written scenario, a map, and a tangle of facts and figures. Your task is to produce a workable plan against the clock, and then to brief it.

It is the most challenging assessment you will face at AOSB. Unlike the others, which typically test a single skill or quality, success in the Plan Ex calls for a wide range of skills. You will be required to:

• Assimilate complex information rapidly.
• Handle ambiguity with comfort.
• Prioritise what is important and disregard what is not.
• Come up with a defensible plan under extreme time pressure.
• Handle multiple speed, distance and time questions in your head.
• Contribute effectively to the group planning phase.
• Brief your plan with confidence.
• Think on the spot while facing probing questions.

It is the assessment that most clearly reflects the demands of being a British Army officer, a role where decision-making, composure under pressure, the ability to plan effectively and communicate it convincingly to soldiers are key requirements.

After all, one day you may have to do this for real in a combat environment, and lives may depend on your ability to get it right.

At Briefing

The session begins with a 40-minute tutorial, where you work through a simple plan and are introduced to the way you will be required to write your answer. You then move into the exam room with a new scenario, and have about 40 minutes to work through it before handing your plan in.

Next, you go with your syndicate into a classroom for a discussion, where you converge on an agreed plan. How the brief itself is then handled varies, and candidate reports differ. Some describe the group delivering a single collective brief, while others say one candidate is asked to give a very short brief on the agreed plan.

The session is described as a tutorial, but do not be fooled. Your performance is being assessed, and the plan you hand in will have a big impact on your category. If you turn up expecting to pick everything up in the 40-minute tutorial run immediately before you do it for real, you are putting yourself at a significant disadvantage.

At Main Board

Main Board strips that scaffolding away. There is no tutorial, and the scenario is harder. You have one hour to work through it on your own, which you should split into roughly fifteen minutes of analysis and forty-five minutes of planning.

After handing in your plan, you go into the discussion with your syndicate, where you have around thirty minutes to converge on a single agreed plan. Then each candidate is called in turn, in a random order, to brief their own plan in full.

This is the plan you wrote and handed in earlier, and the DS will have it in front of them. They will use it to probe your reasoning and will test your mental maths on the spot, while the rest of the syndicate sit in silence watching on. The phase lasts 5 to 10 minutes per candidate, though it feels like much longer.

There is nowhere to hide, and the pressure is real. But it is also a genuine opportunity. Handle it well and you will show exactly the composure, clarity and decision-making the DS is looking for.

Why It Matters

The planning exercise is the assessment that most clearly reflects the demands of being a British Army officer. Decision-making, composure under pressure, the ability to plan effectively and to communicate that plan convincingly are not just what the test measures. They are the job.

The DS treats it accordingly. No other assessment shows them so much about how you think, decide and communicate in a single sitting.

It is the assessment candidates dread most, but it is also the one where preparation is the most important. The scenario changes every time, but the structure never does, and the structure can be learned.

What You Are Handed on the Day

It is much easier to make sense of the method once you have seen what you are actually working with. So before we get to it, here is a scaled-down example. When you arrive in the exam hall, you will sit down at a desk with three pieces of paper:

• The scenario. A written brief setting out the situation and everything you have to work with.
• The map. A sketch of the ground the scenario describes.
• The answer sheet. The six boxes your plan goes onto, handed in at the end of your planning time.

That is all you are given. Next, I will explain a little bit about each of them in turn. I use examples for each.

The Scenario

Two warnings before you read it. First, this is deliberately far easier than the real thing. A genuine Main Board scenario is roughly twice this length, with more locations, more assets and more competing problems, so treat it as a way to picture the format rather than a measure of the difficulty.

Second, this is not practice material. Real planning exercises are carefully engineered, and numbers that look awkward at first glance often fit together surprisingly neatly. This example has not been built with that in mind.

The Map

Here is an example of the map that would come with it. Notice how much it leaves out. There is no scale and no contours, and some of the distances you need appear only in the text. The map deliberately provides you with enough information to come up with a workable plan, without ever removing the need for you to make key deductions yourself. Again, this map is simpler than the ones you will be given at Briefing and Main Board.

The Candidate Answer Sheet

The third and final thing you are handed is the answer sheet. Everything you produce during your solo planning time goes onto it, and you hand it in before the discussion begins. Its six boxes are reproduced below, and the top three hold your analysis of the problem while the bottom three hold your plan.

The real sheet is downloadable from the British Army's officer assessment page. You can find it by clicking the 'What Happens' tab in the Main Board section.

What a Completed Sheet Looks Like

To close the loop, here is the same sheet filled in for Exercise Garron Pass. This is roughly the standard a well-prepared candidate can reach in the hour at Main Board. Notice it is written in short, timed bullets rather than prose, and it does not chase perfection. The DS is marking your thinking, not your handwriting.

A scenario, a map, a blank sheet and a time limit. That is everything you get on the day, and everything else has to come from you. The four phases below are how you turn the first two into the third.

The Four Phases of Every Planning Exercise

Every planning exercise you sit, regardless of the scenario and how much time you have, follows the same four-phase structure. Each phase is distinct, and they run in strict sequence. One cannot begin until the one before it is finished, and each is built directly on the work of the last. It is important to note here that you are responsible for finishing the mission analysis before moving on to the planning. In reality, you are just given a scenario, a map, an answer sheet and a time limit, exactly as you saw above.

That sequencing is what makes early errors so costly. Weak mission analysis leaves you planning around the wrong problem, and a flawed plan makes contributing to the discussion very difficult. An early error compounds, and everything that follows suffers for it.

Phase 1: Mission Analysis

At the start of the exercise you are handed the scenario, and your first job is simply to make sense of it. You will feel a strong pull to start solving the moment you spot a problem. You must resist that temptation.

A plan built on a half-understood situation is a flawed plan, and an error made here will follow you into every phase that comes after. Give this phase about a quarter of your solo planning time.

Read the scenario twice. The first pass is a quick skim for the broad picture, and the second is slower, picking out the key information. From there, your analysis has three parts:

• Problems. List the genuine obstacles standing between you and success, not every minor difficulty the scenario throws up.
• Aims. Rank everything that must be achieved in order of importance. Typically, the main aim will concern the saving of human life.
• Resources & Transport. Note not just what each one offers but what it limits. A vehicle that crosses harsh terrain but has limited fuel is an opportunity and a constraint in the same line.

Be especially wary of aims that are desirable but cannot be achieved without threatening the main aim. They are inserted to test your judgement. Accept that you may not be able to achieve everything, and rank your aims so it is clear what you are willing to give up.

By the end of this phase you should have pinned down the non-negotiable numbers and rules. The deadline, the rates of movement, and anything else that caps what is possible.

Notice that nearly every error in this phase comes from rushing to plan because of the time pressure. It feels productive, and it is counter-productive. Do this phase properly and the planning that follows becomes far easier.

Phase 2: Planning

This is the phase where your analysis becomes a plan, and the plan must be detailed enough that someone could pick it up and carry it out without needing to ask you a single question. It takes about three quarters of your solo time, leaving a few minutes at the end to check your sums.

The temptation here is to commit to the first workable idea you find. What separates strong candidates is the discipline to pause long enough to be sure the plan they commit to is the strongest one available, and not simply the first that came to mind.

• Develop at least two genuine options. Each should be a real route through the problem you could argue for, not one answer with a token alternative beside it.
• Calculate precise timings. This is the core of the phase. Check every figure against the hard limits from your analysis, such as the deadline and the rates of movement.
• Write your preferred plan out in detail. Routes, who does what, exact timings and contingencies. A timeline is the clearest way to lay the timings out, and make sure it is legible.
• Justify your choice. Explain why this plan is the best of your options, including why any risk you accepted was worth taking.

At Main Board the options will tend to differ by route and method, on foot or by vehicle, one path or another. And remember that a flawless plan is not necessarily the aim, as you almost certainly won't have enough time to come up with one. Aim instead for a sensible plan that is clearly thought through and easy to justify.

At the end of this phase you will have settled on a single preferred plan with every timing fixed, plus a short justification for the choice. Your answer sheet is handed in as you leave the exam hall, and it is the document the DS will question you from later.

The mistakes here are avoidable with discipline rather than brilliance. Generate a real alternative, double-check your sums, and make sure the sheet is legible.

Phase 3: Discussion

Until this point you have worked alone in silence. Now you sit with your syndicate, each of you having built a plan in isolation, and the task is to converge on a single collective plan the whole group agrees on. The block lasts approximately 30 minutes.

This phase is about influence, not winning. A candidate whose plan is discarded but who shapes the group's thinking, brings out a good idea from a quieter member, and helps the syndicate move forwards will be judged more favourably than one who grasps the plan well but stays closed to the views of others.

• Listen properly. Genuinely engaging with someone else's better idea counts in your favour, not against you.
• Influence, do not dominate. Engage through reasoning, not volume. The candidate who talks most is rarely the one who is most effective.
• Hold ground on substance, not ego. If you are right about something that matters, make the case. If you are shown to be wrong, concede cleanly and move on.

Get these right and you come across as someone a syndicate would want leading it. Calm, fair, and genuinely useful to the group. I have covered this dynamic in depth in my guide to the group discussion, and almost all of it applies here too.

The candidates who come unstuck here are the ones treating the discussion as a contest to win or a threat to survive, rather than a problem to solve together. Let go of your own plan and focus on getting the syndicate to a good one. A plan is stronger for having been challenged, and the DS knows it.

Phase 4: The Brief

Once the syndicate has agreed its collective plan, the individual briefs begin. You brief the plan you wrote and handed in, not the group's, and the DS will question you from that very sheet. This is the phase candidates dread most.

Together, the brief and the questioning last between five and ten minutes. Keep the following in mind:

• Know your written plan inside out. Make sure you can rebuild every timing from memory, because the timings are what the questioning will probe first.
• Be concise and structured. Signpost as you move through the brief, so the DS always knows which part you have reached.
• Anticipate the questions. You already know where your plan is weakest, because you weighed it against the alternatives. Expect the probing to focus there.
• Never bluff. A confident bluff that collapses under one more question is far more damaging than an honest "I'm not sure".
• Defend a good call, concede a bad one. A challenge is often designed to check whether you will stand behind sound reasoning, or cave at the first push-back.

If the discussion exposed a flaw in your plan, do not pretend it is not there. Acknowledge it and explain what you would now do differently. Showing you can improve your plan under scrutiny reads far better than defending a mistake.

The questioning is meant to apply pressure, so expect to be pushed, and do not read it as a sign you are failing. Stay calm, pause for a moment before you answer, and keep your delivery steady.

Underneath all of this, the DS is judging one thing above all else. Would you be credible standing in front of soldiers? Be confident in your plan, but if someone picks out a genuine flaw, be humble enough to accept it and put it right. That balance of confidence and humility is what they are looking for.

Speed, Distance & Time

Speed, distance and time calculations are crucial throughout the planning exercise, and a single plan can call for dozens of them. The arithmetic is rarely hard in itself. The difficulty is doing it quickly and accurately, knowing that one mistake can throw your plan into disarray, especially if you don't catch it until it's too late. The calculations also follow you into the brief, where the DS will test your mental maths on the spot.

This is a big enough subject to deserve its own guide, so I have written one covering the formula triangle, the conversions worth memorising, and the methods that turn awkward numbers into clean ones. Read the speed, distance and time guide once you have finished here. The same mental arithmetic helps in the numerical reasoning test too.

How to Prepare for the Planning Exercise

Prepare by learning the four-phase structure until it is automatic, drilling your mental maths, and then sitting full scenarios under realistic conditions. Becoming comfortable with the sequence will allow you to handle any scenario that gets put in front of you.

Here is the sequence I recommend:

• Learn the phases first. Know what to do during each phase and how long to use.
• Drill speed, distance and time regularly. Short, frequent sessions build the automatic recall that survives pressure.
• Sit full scenarios under Main Board conditions. Set a 60-minute timer, turn your phone to silent, and remove all distractions.
• Review afterwards. Check your sums, your rankings and your contingencies against a model solution, exactly as you would in an after-action review.

Do not leave any of this until the tutorial at Briefing. As covered above, that session is assessed, and candidates who arrive already comfortable with the format hold a significant advantage.

This cycle is exactly what the Officer Ready Planning Exercise module is built around. It opens with a full worked example built on the Tham Luang cave rescue, rewritten as a genuine Main Board brief, with model answer sheets for the analysis and the plan and the complete operation timeline.

From there the module covers each phase in depth, builds your mental maths through timed drills and map-based scenarios, and provides full practice exercises with briefs, maps and example solutions.

Common Mistakes

Almost everything that goes wrong in the planning exercise traces back to the same handful of mistakes. Avoid these pitfalls:

Frequently Asked Questions

Final Thoughts

The planning exercise deserves its reputation. It is far more complex than anything else you will face at AOSB, and it applies far more pressure. But its structure is completely knowable in advance, and the scenarios are difficult but not impossible.

While the scenario will be new on the day, the four phases will not be. Learn the sequence, drill the maths, and practise until it all feels natural.

And when your own grilling comes, remember what the DS is really testing. Not whether your plan is perfect, but whether you can stand behind a sensible one under pressure. Prepare properly and you will be able to walk out of that room having shown the DS exactly what they were hoping to see. A credible young person who would thrive as a British Army officer.