Psychophysical measurement methods.

Differences in visual acuity measurements obtained with different types of targets.

“…Additional background on applied psychophysical methods in general may be found in Irwin (13), Jones (14), Preston (18), and Rich (20). Guilford (11) briefiy treated the history of the constant methods and described the Muller-Urban method.…”

Some basic considerations in rating scale development: A descriptive bibliography

“…38 Preston concludes that selective discrimination is basic to all measurement. 39 A study of Guilford and Park concluded that evidence, both objective and subjective, favors the Gestalt theory of comparative judgment. 40 Brown's experiments indicated that the conditions of keenest discrimination were also conditions of most reliable judgment.…”