A great benefit of software inspections is that they can beapplied at almost any stage of the software developmentlife cycle. This paper documents a large-scale experimentconducted during an Entity Relationship (ER) Modelinspection meeting. The experiment was aimed at findingempirically validated answers to the question "whichreading technique has a more efficient detection ratewhen searching for defects in an ER Model". Secondly,the effect of the usage of Roles in a team meeting was alsoexplored. Finally, this research investigated thereviewers' ability to find defects belonging to certaindefect categories. The findings showed that theparticipants using a checklist had a significantly higherdetection rate than the Ad Hoc groups. Overall, thegroups using Roles had a lower performance than thosewithout Roles. Furthermore, the findings showed thatwhen comparing the groups using Roles to those withoutRoles, the proportion of syntactic and semantic defectsfound in the number of overall defects identified did notsignificantly differ.