This paper presents a case study of concurrent cognitive actions of a novice and an expert designer. We analyzed cognitive actions of designers using the retrospective protocol analysis method and found evidence of the coexistence of certain types of cognitive action in both novices' and expert designers' protocols. The main difference between the two designers' protocols is the structure of concurrent cognitive actions. While the expert's cognitive actions are clearly organized and structured, there are many concurrent actions that are hard to categorize in the novice's protocol. We also found that the expert's cognitive activity and productivity in the design process were three times as high as the novice's. The results from this single case study raise a question for further studies: do structured and organized acts govern performance in the design process?