The purpose of the thinking processes is to help answer questions essential to achieving focused improvement:
What to change?
What to change it into?
How to cause the change?
Sometimes two other questions are considered as well:
Why Change?
and:
How to maintain the process of ongoing improvement ?
A more thorough rationale is presented in What is this thing called Theory of Constraints and how should it be implemented. A more thorough work, mapping the use and evolution of the Thinking Processes, was conducted by Mabin et al.
Processes
The primary thinking processes, as codified by Goldratt and others:
Current reality tree — evaluates the network of cause-effect relations between the undesirable effects and helps to pinpoint the root cause of most of the undesirable effects.
Evaporating Cloud - solves conflicts that usually perpetuate the causes for an undesirable situation.
Core Conflict Cloud - A combination of conflict clouds based several UDE's. Looking for deeper conflicts that create the undesirable effects.
Future Reality Tree - Once some actions are chosen to solve the root cause uncovered in the CRT and to resolve the conflict in the CRD the FRT shows the future states of the system and helps to identify possible negative outcomes of the changes and to prune them before implementing the changes.
Negative Branch Reservations - Identify potential negative ramifications of any action. The goal of the NBR is to understand the causal path between the action and negative ramifications so that the negative effect can be "trimmed."
Positive Reinforcement Loop - Desired effect presented in FRT amplifies intermediate objective that is earlier in the tree. While intermediate objective is strengthened it positively affects this DE. Finding out PRLs makes FRT more sustaining.
Prerequisite Tree - states that all of the intermediate objectives necessary to carry out an action chosen and the obstacles that will be overcome in the process.
Transition Tree - describes in great detail the action that will lead to the fulfillment of a plan to implement changes.
Strategy & Tactics - the overall project plan and metrics that will lead to a successful implementation and the ongoing loop through POOGI. Goldratt adapted three operating level performance measures—throughput, inventory and operating expense—and adopted three strategic performance measures—net income, return on investment, and cash flow—to maintain the change.
Some observers note that these processes are not fundamentally very different from some other management change models such as PDCA "Plan-Do-Check-Act" or "Survey-Assess-Decide-Implement-Evaluate", but the way they can be used is clearer and more straightforward.
