Framework for understanding the complementary nature of TOC frames: Insights from the product mix dilemma

The product mix problem has been discussed in the management science literature for decades, and in the Theory of Constraints literature since Goldratt and Fox first presented the simple P's and Q's problem. This paper will investigate the product mix dilemma using a variety of Theory of Constraints approaches that complement and extend traditional treatments such as Linear Programming, spreadsheet and graphical approaches. The Theory of Constraints approaches include the product mix algorithm, Five Focusing Steps, Evaporating Cloud and reality trees. The paper will surface insights and draw out implications arising from the use of these different approaches, and show how the choice of Theory of Constraints tool reflects, in essence, a 'framing' of the problem in different ways. We will show that while the various Theory of Constraints frames are complementary in nature, they may also substitute for each other to some degree. As a result, we suggest there is in most cases no one best frame, and the often implicit search for a 'best-fit' frame should be recognized and abandoned. It is argued that there should be greater acceptance of the use of a variety of frames that help us deal with the inevitable ambiguities and complexities that arise in the real world. The application of the framing approach is demonstrated using a real case. Finally, the authors' experience with the use of this and other examples of framing in teaching will be briefly discussed.