Empirical s tudies in the field of the design process s tarted in the 60s. Protocol analysis is among the empirical research methods that have been developed simultaneously with the growth of empirical s tudies. Concurrent with the use of protocol analysis for researching in the field of the design process, analysis methods have been presented by some researchers, which can be used with the protocol analysis method in order to analyze the s tructure of the design process. Among these analysis methods, problem behavior graph, decision tree, linkography, and extended linkography could be mentioned. The problem behavior graph is based on problem-solving theories. In the decision tree method, the extracted data from protocol analysis is used for the perception of decision-making processes. Linkography is another method for analyzing the s tructure of the design process. In this method, the design process of a designer is unfolding by drawing a graph, which is called linkograph. This paper considers making a s tudy and comparison of these different analysis methods by the use of sys tematic review. By comparison of diverse analysis methods, two approaches could be recognized, formal and informal ones. In the formal approach, the design is mentioned as a logical research process of solving the design problem. The second approach is informal. In this one, the design process is mentioned as a reflective conversation with the situation. In this approach, which is based on Donald Schon’s theories, the design process is referred as an argumentative process.
