The Power of Iterative Adaptive Work

April 25
8 minute read

As a coach, it is nice to have some simple ways to show people the power of iterative adaptive work as found in Real Agility™. This quick little exercise is an excellent way to demonstrate that power as compared to the weakness of the waterfall approach.  You can use the exercise in both coaching and training situations.  You need a group of participants, at least 10, and an even number of people.

Applicability of the Exercise

Use this exercise when introducing Agile methods to people who have little or no formal exposure, and who have previously worked in an up-front planning style.  This exercise is particularly powerful with technical people such as software developers, analysts, engineers, architects, etc.  Others will also understand it easily.

Exercise Setup

This exercise requires only a pen and a single piece of paper or note card for each pair in your group.  As the facilitator, you will also want a flip chart or whiteboard to write summary results of the two stages of the exercise.  You will also need a 60 second countdown timer which you can watch to see as seconds are passing.

Introducing the Exercise

Describe the exercise to the group as follows:

“The next activity will help us understand why iterative adaptive work methods such as Scrum are better for many types of work.  We will use a simple problem solved in two different ways in order to demonstrate quantitatively how working with up-front requirements analysis is less effective than the power of the agile iterative/adaptive approach found in Real Agility™.  In order to run this exercise, you need to find a partner to work with.  Please do so now.”

As the facilitator, you may wish to add additional constraints on organizing, but since the exercise is short, don’t make the organization complicated.  Often it’s best for people to partner up with people they are sitting beside.

Framing the Activity

Once everyone has a partner, continue as follows:

“In this exercise, we will solve the problem of communicating a number to another person.  Of course, we could just tell them, but that doesn’t allow us to simulate the more complex problems that we usually deal with in real life.  So, we are going to add some rules to how we communicate.  One person in each pair will choose a number at random between 100 and 999.  The other will try to figure out the number chosen.  Let’s call the person with the number the ‘Customer’.  Let’s call the other person the ‘Engineer’.  You will have 60 seconds to, hopefully, communicate the number successfully.  I will keep time and guide you through the process.  The first time we try to solve this communication problem we will use different rules than the second time.  The rules are meant to illustrate the difference between up-front analysis and iterative, adaptive problem-solving.”

Note that the numbers must have 3 digits and that is why we make them between 100 and 999.  Show the participants that you have a 60 second countdown timer ready.

Round One – “Waterfall”

Make sure you have everyone’s attention and then continue as follows:

“Listen carefully while I explain the rules for the first round.  The Customer in each pair will write down the random number chosen between 100 and 999 on a piece of paper, making sure that their partner, the Engineer, does not see the number.  The Customer must come up with clues about the number.

However, the Customer cannot use any math either explicitly or implicitly in the clues.  For example, if the number is ‘256’, a good clue is ‘the first and second digits are rotationally symmetrical on an old-style LED display’, and a disallowed clue is ‘it is an even number’ because it uses a mathematical feature.  Of course, saying the number or any of the digits outright is disallowed.

Coming up with clues is expected to be challenging, but hopefully in 60 seconds you will be able to provide at least a few clues.  As you create clues, tell them immediately to your Engineer.  During this first round, the Engineer cannot ask questions.  At the time when there are 5 seconds remaining, I will let you know with a loud <whistle>|<bell>|<clap>.  The Engineer immediately states a guess for the number that they think is correct or might be close.  Write that number down.

When the time is up, calculate the difference between the two numbers.”

Once everyone has calculated the difference, poll the class to find the pair with the smallest difference between the two numbers and the pair with the largest difference.  Write down the range of difference on your flip chart or whiteboard under the heading “Round 1”.  Also, find out if anyone (and how many) actually got the correct number – this is usually none.  If anyone did get the correct number, remember the pair for the debrief where you will come back to this occurrence.  Give the group a very short pause (maybe 15 or 20 seconds while you write the results up) to think and relax.

Round Two – “Iterative Adaptive”

Then, get everyone’s attention again and continue to the second round as follows:

“Switch roles with your partner.  If you were the Customer you become the Engineer and vice-versa.  Again, as a Customer, you write down a number between 100 and 999 on a piece of paper so the other person can’t see it.

Now, the rules are very different.  I need to emphasize this: the rules are very different.  We are now switching to an iterative adaptive approach to communication and problem solving.

When I start the countdown timer, the Engineer guesses a number.  The Customer immediately tells the other person if the guess is low, high or correct by saying “your guess is too high” or “your guess is too low” or “your guess is just right”.  The Engineer now has another guess, and the Customer again responds with low, high or correct.  Continue this as many times as possible or until the Engineer has the correct number.  At the time when there are 5 seconds remaining, I will let you know with a noise.  Write the Engineers most recent guess down on paper.

When the time is up, calculate the difference between the two numbers.”

Again, once everyone has calculated the difference, poll the class to find the pair with the smallest difference (usually there are many who have achieved the correct number), and the pair with the largest difference.  And, again, write down the range of difference on your flip chart or whiteboard under the heading “Round 2”.  Give the group a very short pause to think and relax.  If some conversations about the exercise start amongst the group, use those to begin the debriefing.


The following questions can help you with debriefing the exercise.

  1. How was the first part of the exercise like the waterfall method?
  2. Was it successful/how close did you get?
  3. How was the second part of the exercise like an iterative adaptive method?
  4. Was it successful/how close did you get?
  5. What are some of the limitations of this exercise?
  6. How does it compare to your real-world work environment?
  7. How can you apply the iterative adaptive techniques from this exercise to your real-world work?
  8. What other interesting things did you notice about this exercise?

As a facilitator, it is important to help the group express conclusions about the exercise, rather than feeding them to people.


A couple possible pitfalls occur with the exercise and being prepared for them can help with the debrief:

  • If more than one pair guesses the correct number in the first round.  This is highly unusual, but is likely due to the partners not following the instructions correctly.  Ask some detailed questions about how they worked in the first round to see if there was a problem with following the rules.  For example, maybe the Engineer asked questions about the clues during the sixty seconds, therefore not following the rule about only guessing at the end.  Or, maybe the Customer chose the number 5 (not following the rules about the allowed numbers) and told the Engineer the clue: “it’s a single digit”.  This would allow the Engineer to have a much higher chance of guessing the correct number.
  • If very few pairs in the second round get the guess correct, it is likely related to one of two problems.  Either they didn’t do fast enough repetitions of the guessing process, or the Customer was unclear in their feedback about the guess being too high, too low or just right.  Again, check in with the group to see if this happened.

In general, if there are problems of this nature, you might choose to get the whole group or a few of the pairs to re-do the round.  Since it is a very fast exercise, this is usually feasible, and is really the best way to address the problems.

The Power of Iterative Adaptive Work – Real Agility™

The explanation for this exercise is simple.  In an iterative adaptive work approach, fast feedback helps problem-solving efforts converge quickly on a Customer’s needs.  In the simulation, you set up the environment to mimic some of the difficulties of communicating abstractly vs. communicating concretely. Most people will easily see the difference between these two approaches.  However, some people might struggle with the idea that one can’t afford guesses.  That can lead to a fertile discussion about the role of complexity in planning and analysis.

Acknowledgements: the second part of this simulation exercise comes from a discussion with Jim York of FoxHedge Ltd back in 2006.

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