Estimation of Quality Scores from Subjective Tests - beyond Subjects' MOS
Subjective tests for the assessment of the quality of experience (QoE) are typically run with a pool of subjects providing their opinion score using a 5-level scale. The subjects? Mean Opinion Score (MOS) is generally assumed as the best estimation of the average score in the target population. Indeed, for a large enough sample we can assume that the mean of the variations across the subjects approaches zero, but this is not the case for the limited number of subjects typically considered in subjective tests.