Comparing entropy measures of idea links in design protocols: Linkography entropy measurement and analysis of differently conditioned design sessions

This paper explores using Shannon’s entropy of information to measure linkographs of twelve design sessions which involved six architects in two different experimental conditions. The aim is to find a quantitative tool to interpret the linkographs. This study examines if the differences in the design processes and the design outcomes can be reflected in the entropic interpretations. The results show that the overall entropy of one design condition is slightly higher than the other. Further, there are indications that the change of entropy might reflect design outcomes. 1. Background The aim of this study is to explore the use of a quantitative tool – entropy measurement of a linkograph – in protocol studies of designers in order to provide insight on design activities, especially at the early stage of idea development. This section presents the necessary background for this study; they are the construction of linkography, the measurement of linkography using Shannon’s entropy, and the theory and method of the blindfolded designing experiment. 1.1. LINKOGRAPH Linkography was first introduced to protocol analysis by Goldschmidt (1990) to assess design productivity of designers. It is a technique used in protocol analysis to study designers. The design protocol is decomposed into small units called “design moves”. Goldschmidt defines a design move as: “a step, an act, an operation, which transforms the design situation relative to the state in which it was prior to that move” (Goldschmidt 1995), or “an act 2 COMPARING ENTROPY MEASURE OF IDEA LINKS of reasoning that presents a coherent proposition pertaining to an entity that is being designed” (Goldschmidt 1992). A linkograph is then constructed by linking related moves. It can be seen as a graphical network of associated moves that represents the design session. Figure 1 is a linkograph with 3 moves.