Upper Baseline

In accessibility evaluation research, an upper baseline is a high-quality reference stimulus used to establish the best achievable performance against which other systems are compared. For sign language animation studies, this might be a video of a human signer or a carefully crafted animation. The choice of upper baseline can significantly affect evaluation results—video baselines typically receive higher subjective ratings than animation baselines, and their presence can depress scores for other stimuli by 10-20% through comparison effects.