The main purpose of evaluation is to collect information for making two types of
decisions, formative and summative. These types of decisions are made based on the evidence
revealed by the evaluation results, and both of them greatly affect teachers’ professional lives
(Berk, 2005). Formative decisions are made by teachers to improve their teaching performance,
while summative decisions are made by administrators to judge their personnel. These
decisions in particular need to be made on a fair basis because they have crucial importance to
a teacher’s career. Thus, it is important to identify appropriate evaluation models or methods
that best fit different educational settings and disciplines.