In direct
observation methods, the relationship between the trainee and the
assessor may be a source of positive or negative bias, hence the need
for multiple assessors. When used for progression requirements,
direct observation tools may be problematic given the natural
tendency to avoid negative evaluations. Assessor training and the
use of external examiners may help to alleviate this problem, but it
is arguable that the direct observation tools should not be used in
high-stakes assessments