An Evaluation Of The Pugh Controlled Convergence Method

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Part 1. Research Summary
An evaluation of the Pugh controlled convergence method
The main objective of this paper is to evaluate and demonstrate that the Pugh controlled convergence method is a valid tool for decision making. The authors begin by stating a few critiques that other authors have made to the Pugh’s method, for example: “Pugh Controlled Convergence uses multiple people in theprocess in which a decision must be made [Hazelrigg, 1996], involves multiple criteria [Franssen, 2005], separates the concern into multiple criteria [Saari, 2004] and uses pair-wise comparisons [Saari, 2004]” [1]. To answer these critiques, the authors want to evaluate “the role of the datum concept, the convergence of expert opinion based on investigation and generation of new alternatives. At thesame time, ascertain whether or not the reported undesirable behaviors of Pugh’s method actually arise under realistic conditions. If they do arise, determine their severity and suggest how to avoid them." In order to understand the paper it is important first to understand what the Pugh method is and what it consist of.
According to the authors Pugh stated that “after market investigation,product design specification and concept synthesis, the design team should engage in the iterative process of culling down and adding to the set of concepts with the purpose or goal to converge on a strong concept that has promise of out-competing the current market leader and help the team understand the reasons for their choice.”
The Pugh process is presented in a matrix, where the columns of thematrix are labeled with a description in words or drawings of different concepts. The rows of the matrix are labeled with concise criteria by which the design concepts will be compared/judged. A datum, often a product leader in the market, is selected and all the other concepts will be compared to it, if a criteria of the concept is better than the datum’s a “+” is assigned, if it is worse a “-“and if it is determined to be the same a “S” is assigned. Based on this, information, we can conclude that in order to use the Plugh’s method, a product with similar characteristics must exist, which will only generate a variant design or can it be also used to evaluate different function structures that a new product must have?
Another important point abut Pugh’s method is that there is no votingprocedure to select or assign values, if a person of the team disagrees with a + or -, a discussion takes place in which “facts are brought to light, a clarification is made about what a concept actually entails or a clarification of what the criterion actually means is made. If the discussion leads to an agreement, a +/- is assigned if it persists for a significant length of time, an “S” isassigned.” This represents a flaw in the method, because if an S is assigned, when there was a disagreement, then that criterion is not evaluated. This
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can lead to taking a wrong decision. The “S” in the evaluation can also denotes, that the differences between the concept and the datum are controversial and cannot be determined yet. After the first evaluation, the number of +,- and S are countedand presented as rough measure for each concept (this represents a contradiction that will be later mentioned and explained). According to the authors “the meaning of these scores are often misinterpreted as a mean to choose a single winning design”. The first run or evaluation of the Pugh method might lead to the reduction of design concepts, but rarely to one [1]. This reduction in concepts,leads to an iteration process in which the concepts are evaluates again. This process generates the following questions: How is the second run differ from the first one if the criterion doesn’t change? How many iteration runs are required to get a solution? If the criterion changes, is it valid to eliminate weak concepts from the previous run? The answers to these questions are that different datum...