Magnitude estimation is an experimental technique used to quickly and easily determine how much of a given sensation a person is having. Stevens was the first experimenter to ever suggest using magnitude estimations to quantitatively scale sensation (Allard, 2001). In a magnitude estimation experiment subjects are presented with a standard stimulus (a modulus) and are told that the stimulus has a magnitude of a certain value, like 20. The subjects are then presented with a series of stimuli that vary in intensity and are asked to assign each of the stimuli a number relative to the standard stimulus. For example, if the current stimulus is twice as intense as the standard stimulus it should be called 40 or if it is half as intense, it should be called 10 (Snodgrass, Levy-Berger & Haydon, 1985). Scaling is in no way about absolute accuracy of judgments; scaling is about the relative relationships between judgements of stimuli of different intensities. The experimenter does not use a standard stimulus in an attempt to get subjects to make judgements high in absolute accuracy…they are just trying to get subjects to use similar numbers to make results easier to interpret (Allard, 2001).