behavioural observation scale
A technique for evaluating the performance of an employee which can be used as part of the appraisal process. Like behaviourally anchored rating scales, the BOS technique involves a process of identifying the key tasks for a particular job, but the difference is that employees are evaluated according to how frequently they exhibit the required behaviour for effective performance. The scores for each of these observed behaviours can then be totalled to produce an overall performance score. In such instances, the various measures of behaviour are normally weighted to reflect the relative importance of the measure to the overall job.