A common mistake for newcomers to the Goal Tree is to understand the tree structure as a hierarchical system, with the most important Necessary Conditions on the top – the closest on the Goal – and the least important at the bottom of the tree, farther away from the Goal. In fact, the relative position of a Necessary Condition in a Goal Tree is not importance related but time related.
The Goal Tree is a logical structure of Necessary Conditions to achieve a Goal. The Goal statement is the top-most entity of the Tree, the ending point. The Necessary Conditions underneath are building blocks if you will, necessary to achieve the Goal.
Necessary Conditions must comply to the necessity logic, or put simply, answer the condition dictated by the little sentence “In order to achieve…[condition or objective], we must..[Necessary Condition]”. A Necessary Condition is an enabler for the condition or objective above it to be fulfilled.
The Goal Tree is built from top to bottom, starting with the Goal Statement, and then listing all Necessary Conditions to achieve it. The first level of Necessary Conditions is dependent on a second level of Necessary Conditions (NCs) necessary to fulfill them, thus the first level NCs become intermediate objectives to the second level, and so on to the the very bottom of the Tree.
Achieving Necessary Conditions in sequence
Now once the Goal Tree is completely built, it is a benchmark and a roadmap all together to achieve the Goal. In order to achieve the Goal, all Necessary Conditions must be fulfilled and because each Necessary Conditions is the enabler allowing the above condition(s) to be fulfilled, Necessary Conditions must be fulfilled in sequence from the bottom to the top.
In other words, an organization has to work its way to achieving its Goal from bottom to top of the Goal Tree. And here we are with a hierarchy in time: the Necessary Conditions at the bottom must be fulfilled first so that the upper conditions can be fulfilled.
As Necessary Conditions are necessary, there is no ranking of importance, they are equally important. If a NC could be omitted or only partially fulfilled and the Goal be achieved anyway, then it wasn’t a true Necessary Condition.
Necessary Conditions are enablers, so as long as they are not fulfilled, the sequences of NCs above them are not enabled.