The staircase procedure is used in psychophysical and electrophysiological methods by increasing or decreasing the sound pressure level depending on the outcome of the last trial. Usually, the level is initially high and decreases at the beginning until the sound is not heard anymore. Then the sound level is increased again until the sound is heard again. The points of inflection are called "reversals". The staircase procedure is defined by the initial and final step size (difference between sound pressure levels played back) and the number of reversals (how many reversals are conducted before the measurement is finalized).