Software inspections have attracted much attention over the last 25 years. It is a method for static analysis of artefacts during software development. However, few studies look at inspections of entity-relationship diagrams (ER-diagrams), and in particular an evaluation of the number of defects, number of false-positives and the types of defects that are found by most reviewers. ER-diagrams are commonly used in the design of databases, which makes them an important modelling concept for many large software systems. This paper presents a large empirical study (486 subjects) where checklists were used for an inspection. The goodness in the evaluation is judged based on the type of defects the reviewers identify and the relationship between the detection of real defects and false positives. It is concluded that checklist-based inspections of entity-relationship diagrams is worthwhile.