Tools

                    The Prerequisite Tree

The Prerequisite Tree allows us to
 
break down a seemingly insurmountable task into its various obstacles. In other words, it highlights the obstacles that come between us and the completion of the task. In this way everyone involved has a clear definition of what makes the task seem insurmountable

realise that every obstacle can be overcome by attaching a corresponding intermediate objective, thus giving everyone involved a more consistent strategy

understand that correct timing will make it possible to achieve all the objectives and therefore co-ordinate the tactics/actions of everyone involved
 

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Example: Tea Mission (we want to have a nice cup of tea in the wilderness)
 

Participants in this ambitious target may raise the following obstacles

Obs-1 We do not have material to burn
Obs-2 Collection of such material is not allowed in  the wilderness.
Obs-3 There could be a strong wind
Obs-4 We do not have matches
Obs-5 We do not have  cups
Obs-6 We don’t have a container to boil the water

Some of the obstacles are not really difficult to overcome, but we had better  not forget them. Actually, we can combine obstacles 4-5-6 into one, such as we always forget to bring everything needed for preparing tea.

Obs-1 We do not have material to burn
Obs-2 Collecting of such material  in the wilderness is not allowed
Obs-3 There can be a strong wind
Obs-4 We tend to forget to bring everything needed to prepare the tea

Obstacle 4 can be overcome by

Intermediate Obiective-4.1:  We have a packing list for the tea activity
Intermediate Obiective -4.2:  The tea kit is loaded into the car

Both Obs-1 and Obs-2 can be overcome by taking some pieces of wood with us in the trunk of the car.  In other cases people may suggest that if the objective is to have the tea, we may not actually need to have a fire, but a mobile gas apparatus would do the trick.  Creativity is wonderful when you know how to channel it.

Obs-3 can be overcome by having a sheltered place to light the fire.

 At this point we have a list of three Intermediate Objectives (IOs)

IO-1:     We have some pieces of wood in the trunk of the car.
IO-3      We have a sheltered place to light the fire
IO-4.1:  We have a packing list for the tea activity
IO-4.2:  The tea kit is loaded into the car

The last bit is to sort the sequencing of the Intermediate Objectives (IOs), which one has to be in place before the other, and which IOs are not dependent and can be achieved in parallel.

IO-4.1 must be achieved before IO-4.2, otherwise we may prepare and load an incomplete kit into the car.

IO-1 can be achieved in parallel to IO-4.1 and IO-4.2 unless we want to load the pieces of wood last, so that they will be the first to be unloaded from the car.  In this case we state that IO-4.1 and IO-1 must be achieved before IO-4.2.
IO-3 will be dealt with when we get to the picnic place and therefore is the last one to achieve before we start the process of preparing the tea. Technically one can say that IO-3 is not dependent on the completion of IO-4-2.  But, what is the point of searching for a sheltered place if we don’t have pieces of wood or the tea kit?

We can put it in a schematic form – the IO Map:
 

the same map with contents:  
 
Now we are in the position where we have a map that will help us on the journey of introducing the change into our reality. The IO - Map draws the logical connections of all the necessary prerequisites that must be achieved.  This is why the IO-Map is also called a Prerequisite Tree (PRT).

When all IOs are agreed on, the leader assigns responsibility to individuals to handle the specific Intermediate Objectives (IOs).  The PRT is the way to synchronize the efforts of the team members in achieving the ambitious target.
 

The use of PrT and TrT form the backbone of a synchronized work mechanism and in this respect contain the basic seeds of project management.