This paper compares the Chen Entity-Relationship diagram with the Structured Analysis and Design Methodology (SSADM) “Logical Data Structure.” The authors took 36 students with no knowledge of either notation and taught them the essentials. They then tested to see how well the students recognized if texts matched different diagrams, and asked for preferences and reasons. There are two significant results: the students figured out SSADM diagrams quicker, and preferred SSADM for its simplicity.

The experimental design and statistical analysis are excellent. The paper is well written, and easy to understand. I was on the team that designed SSADM, and I would love to see evidence that we were right. However, this experiment is biased. First, the models only had binary relations. SSADM does not need a box for many of these; Chen does. Second, the authors ignored the SSADM rule that “a many-to-many link must always be resolved by creating a new link entity” [1]. This rule adds boxes to SSADM data structure diagrams. Often, they are useful. We need an experiment to see if these cause confusion, plus a survey of how useful they have been in practice.

This paper should be read by all involved in methodologies. It supports, with good scientific evidence, the old rule: “keep it simple, stupid!”