Abstract
This study considers how to obtain some theoretical expressions to measure efficiency of order-picking. For this purpose, we formulate the model of order-picking operations aiming at travel time and treat the IQ-curve as continuous representation. These enable us to derive various quantitative equations with regard to operation times of single and total picking. Acoording to the derived equations, numerical examples give us such important implications that total picking is more advantageous as order size decreases and that the composite policy of single and total picking should be recommended when the IQ-curve is very sharp.
