Instructions for Assessors (Subjects)

Before carrying out the experiments, some instructions should be given to the assessors. These instructions include the method of assessment, the types of impairment or quality factors likely to occur, the grading scale, the sequence and timing. This information should be explained and given to the subjects in a written form. The range and type of impairments should be presented in preliminary trials. Training trials may be given to subjects to familiarize them with the task they will perform.