Tools from the Theory of Constraints

Anthony R Rizzo


Editor’s note: Tony Rizzo is a "Jonah" - a practitioner of the Theory of Contraints and organizational improvement as taught by Elihu Goldratt, whose books "The Goal" and "It’s Not Luck" have had profound impact on throughout the industrial world. Tony participated in a TRIZ workshop with Ellen Domb and Jim Kowalick in February, after extensive self-study of TRIZ. The following is exerpted from his letter on the useful interfaces of the techniques.

Often, limited creativity is THE constraint on a corporation. TRIZ elevates (breaks) this constraint. This, at least, is the high-level view. There is more as we get into the working levels of the techniques.

The TOC tool that clearly has the greatest applicability is the Evaporating Cloud. [During introductory TRIZ training ] I was able to identify and describe the conflict much more quickly than the others in my group due to my TOC background. In TOC terms, I wrote the cloud, after which the solution became apparent.

One of the great synergies that I see between TRIZ and TOC is this. The 40 inventive principles are what TOCers would call "injections," i.e., solutions that break the inventor's underlying assumptions about the problem. Using the Evaporating Cloud alone requires us to surface these assumptions and to break them, thus arriving at a no-compromise solution. Using TRIZ alone, without the Evaporating Cloud, causes us to struggle with the definition of the conflict. Many people have trouble identifying and defining the conflict. But the Evaporating Cloud and the 40 inventive principles together make for a dynamite combination. The Evaporating Cloud provides a great deal of clarity regarding the conflict. Then, the inventive principles provide a list of 40 possible solutions, some of which break one or more underlying assumptions. It's as if one were working in reverse, thus the entire process becomes much easier.

Two other sources of synergy are TOC's Current Reality Tree and Future Reality Tree. These are sufficiency-based logic diagrams. They are constructed and verified against a set of rules, known as the Categories of Legitimate Reservations (CLR). The CLR are the rules of logic. The Current Reality Tree and the Future Reality Tree will be very useful in identifying what is _really_ needed, to achieve a set of desired functions.

Now that I think of it, the Prerequisite Tree also will be useful. The Prerequisite Tree is a necessity-based logic diagram. It's used to identify the major obstacles between, say, a project team and an ambitious objective. For each obstacle, then, members of the team identify conditions (things) that overcome the obstacle. Here is where TRIZ would provide a great deal of power. With TRIZ, the members of the project team could identify inventive solutions to the technical obstacles.

As you can see, I'm pretty excited about the combination of the two bodies of knowledge. I'll soon embark on a combined TRIZ/TOC course. It should be very exciting indeed.