Premise: While all of the central groups had staffs ranging from 3 to 17 people permanently assigned to the group, comparing the size of These groups is of limited value because of wide variations in the (1) sizes of the organizations we studied, (2) inherent riskiness of their operations, and (3) the additional support the groups received from other organizational components and from numerous subordinate security managers and administrators.

Hypothesis: Some groups had no staff.
Relation: contradiction