Simple adaptive testing with the weighted up-down method.

This paper proposes a method for adaptive testing that is less complicated than the commonly used transformed up-down methods (1 up 2 down, 1 up 3 down, etc.). In addition, the weighted up-down method can converge to any desired point of the psychometric function. The rule is very simple: Each correct response leads to a decrease in signal level, each incorrect response to an increase. The only difference from the simple up-down method (1 up 1 down) is that the steps upward and the steps downward are of a different size. The straightforward construction of the novel procedure pays off in efficiency and stability: A Monte Carlo simulation reveals a definite advantage, though small, of the weighted up-down method over the 1-up-2-down rule.