A Guide to Implementing the Theory of Constraints (TOC)





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Categories of Legitimate Reservation

The categories of legitimate reservation are proof-reading tools for logical cause and effect trees. As such they seem to have a dual purpose;

(1)  Raise valid concerns about cause and effect rigor.

(2)  Not raise resistance or defensiveness of others in the process.

Noreen et al., published the first concise description of the legitimate categories of reservation, and since then several more detailed descriptions have also been published (2, 3, 4).  The following is a concise summary of each of the reservations.  Please refer to the more detailed texts for further information.

Clarity Reservation

Requesting additional explanation, not fully understanding the cause and effect relationship or the individual entities.


Entity Existence Reservation

Questioning the existence of the cause or effect entity.


Causality Existence Reservation

Questioning the existence of the causal link between the cause and the effect.


Predicted Effect Existence Reservation

Using another effect (B) to show that the hypothesized cause does not result in the initial effect (A).


Insufficient Cause Reservation

Explaining that an additional non-trivial cause (B) must exist to explain the observed effect.


Additional Cause Reservation

Explaining that an additional cause which adds to the size of the observed effect must exist.  Neither cause by itself can account for the effect.



Being redundant in stating the cause and effect relationship.

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(1) Noreen, E., Smith, D., and Mackey J. T., (1995) The theory of constraints and its implications for management accounting.  The North River Press, pg 161.

(2) Dettmer, H. W., (1997) Goldratt’s Theory of Constraints: a systems approach to continuous improvement.  ASQC Quality Press, pp 30-61.

(3) Dettmer, H. W., (1998) Breaking the constraints to world class performance.  ASQ Quality Press, pp 57-68.

(4) Scheinkopf, L., (1999) Thinking for a change: putting the TOC thinking processes to use. St Lucie Press/APICS series on constraint management, pp 41-67.

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