Data Flow Diagrams and Use Cases are two popular methodologies in teaching as well as in practice. For the last 4 years, we have been using both methodologies in our Systems Analysis course. Questionnaire results indicate that students find the Use Cases methodology slightly easier to understand. However, students believe that Data Flow Diagrams are significantly better at communicating with users and programmers.
From Fall 2003 through Fall 2007, fifteen sections of our Systems Analysis course were introduced to structured analysis techniques as well as object-oriented methodologies. The same instructor taught all fifteen sections.
We assigned each section to either a “DFD First” or a “Use Case First” treatment group. This was done in order to balance and investigate the sequence effect of introducing one methodology before the other. For example, in the Spring 2006 semester, we assigned one section with 26 students to the “DFD First” treatment group and the other section with 19 students to the “Use Case First” treatment group.