Bandwidth is the extent to which the job performance domain is covered by an assessment. Ideally, all job tasks are included in a simulation, but that is a practical impossibility, particularly for complex and multifaceted jobs (Felker, Curtin & Rose, 2007). This leaves open the possibility that the simulation will be job-related but deficient in that it is not sufficiently comprehensive to reflect the range of behaviours required for the job or role, and subsequently can attenuate criterion-related validity (Callinan & Robertson, 2000). In constructing simulations for selection, care must be taken to ensure the inclusion of a representative sample of job tasks or activities or inclusion of those that are the most critical to job performance (Campbell et al., 1990; Gatewood et al., 2008; Green & Wigdor, 1991). When simulations are used with other assessments, it is advisable to identify the critical job elements not assessed or not well measured and to target the simulation to those areas.