Quality Assurance of exam scripts is important in assuring the integrity of the exam and that it assesses the achievement of the student against the subject learning outcomes.
Validity of exam scripts should enable measurement of the achievements of skills intended to the achieved by the learning outcome. For example: if depth of knowledge is required to be assessed, then we need to design long answer/essay type questions with adequate direction.
Reliability of exam script allows consistency in marking and to differentiate between the levels of the performance.