Hello TOC

Advanced Fundamentals · Lesson 7 of 8

Causing the change

The third question: how to cause the change? Map the obstacles, set intermediate objectives, sequence the actions, and for a whole organisation, connect strategy to tactics in one tree. And coach by asking, not telling.

16 min · Not completed yet

A solution nobody implements is worth nothing. TOC’s third question is how to cause the change? It has its own tools.

The prerequisite tree: what must be in place?

The prerequisite tree (PRT) starts from the injections and asks what stands in the way.

  1. For each injection, list the obstacles: what exists today that prevents it?
  2. For each obstacle, set an intermediate objective (IO): a condition that, once achieved, removes the obstacle or gets around it.
  3. Arrange the intermediate objectives with necessity logic: which must come before which?

It uses the same in order to … we must … logic as the conflict cloud, but points it at the future. In a cloud, the blocking element is an assumption; in a prerequisite tree, it is an obstacle. For daily use, the tree is often simplified into an IO map: the same logic as a flat list.

The transition tree: what do we do, in what order?

The transition tree (TRT) turns intermediate objectives into actions. Each step states three things:

  1. The need: why this action is necessary now.
  2. The action: what is done.
  3. The predicted effect: what it produces, which becomes the condition for the next step.

Use it where the sequence matters: a key negotiation, a buy-in meeting, a change done for the first time. And if reality doesn’t follow the plan, the tree shows exactly where and why it broke.

Exercise: which tool would you use?

  • “Before we can release orders by priority, what’s stopping us?”
  • “Plan exactly how we take the union through the new shift pattern, step by step.”
  • “Why do we have late orders, high stock and constant overtime all at once?”
  • “What conditions must exist before the central warehouse can hold the buffer?”

The strategy and tactics tree

For a whole organisation, the most complete tool is the strategy and tactics tree (S&T tree). It holds an entire change in one connected structure, from the top objective down to specific actions, so everyone can see how their work connects to the goal.

  • Every node is a pair: a strategy (what for?) and a tactic (how?).
  • Going down through a tactic asks: how exactly is this done? Each level breaks into several steps below.
  • Going up through a strategy asks: why do we want this? The answer is the strategy one level up.
  • Each step carries three explicit assumptions: why this tactic achieves this strategy (and why not an alternative), why this step is necessary, and why the steps together are sufficient. Anyone can challenge them, which keeps the tree honest.

A typical S&T tree for a manufacturer might run: become ever-flourishing → build a decisive competitive edge (such as reliable short lead times) → build the operational capability (choke the release, buffer management) → capitalise on it in the market → sustain it with ongoing improvement.

Coaching by asking: the Jonah role

In Goldratt’s novel The Goal, the mentor Jonah never hands the hero an answer. He asks questions until the hero sees the situation clearly and reaches the conclusion himself. In TOC, a coach who leads this way is called a Jonah.

Why ask instead of tell? A solution people reach themselves is owned, understood and defended. A solution they are handed is doubted and dropped at the first obstacle. Good Jonah questions point attention at the constraint, surface an assumption being treated as fact, make a conflict explicit, and ask about the effect on the whole system.

Pause and think: a plant manager says, “We need a new machine; we’re always behind.” What would a Jonah ask?

  • “How much does the machine cost?”
  • “Which supplier will you use?”
  • “How many hours a day does your busiest machine actually work on what customers need now?”
  • “Why didn’t you ask earlier?”

The question sends attention to the constraint and to hidden capacity, and lets the manager discover the answer: exploit before you elevate.

Check your understanding

Answer all five. Get four right to complete the lesson.

1. In a prerequisite tree, what blocks an injection is called…

  • An assumption
  • An obstacle
  • An undesirable effect
  • A tactic

Each obstacle gets an intermediate objective.

2. Each step in a transition tree states…

  • Only the action
  • The budget and owner
  • The deadline
  • The need, the action and the predicted effect

So the logic of the sequence is explicit.

3. In a strategy and tactics tree, each node pairs…

  • A strategy (what for?) with a tactic (how?)
  • A cause with an effect
  • A need with an action in conflict
  • A person with a task

And carries explicit assumptions anyone can challenge.

4. Why does a Jonah ask questions instead of giving answers?

  • To save time
  • Because the coach doesn’t know
  • A solution people reach themselves is owned and defended
  • To test people

Ownership matters more than cleverness in real change.

5. TOC’s three questions, in order, are…

  • Who, what, when?
  • What to change, what to change to, how to cause the change?
  • Plan, do, check?
  • Why, how, how much?

And the Thinking Processes answer each one.