A survey of assessment practices revealed that in about half the organizations, surveyed assessors had to be certified before serving in this capacity, which usually involved successfully completing a training program. Substantial increases in reliabilities can be obtained as a result of training observers. In one study, for example, mean interrater reliabilities for untrained observers were .46 on a human relation dimension and .58 on an administrative-technical dimension. For the trained observers, however, reliabilities were .78 and .90, respectively. Assessors usually are trained in interviewing and feedback techniques, behavior observation, and evaluation of in-basket performance. In addition, the assessors usually go through the exercises as participants before rating others. Training may take from two days to several weeks, depending on the complexity of the center, the importance of the assessment decision, and the importance management attaches to assessors training.