Abstract: Since Michael Fagan first described inspections in 1976, much literature has been written describing the results from investigations, evaluations and use of inspections. Many research papers report on how an inspection team's size affects the efficiency and effectiveness of inspections. This study puts the individual reviewer and the contribution he or she makes to the team's effectiveness in focus. To illustrate the magnitude of the impact an individual reviewer has and the difference in contribution between the best and the worst reviewer, data from a number of empirical inspection experiments is analysed. The lost effectiveness is found to be in average 0.16 when removing one reviewer from a two-reviewer team down to 0.04 for six-reviewer teams.