The motor quotient. A method for the early detection of motor delay.

A motor quotient was calculated by dividing the age of a child's best motor achievement by his or her chronologic age. A quotient less than 50 was said to predict gross motor delay (walking at or later than 24 months). Applying the quotient to 144 8- to 18-month-old children yielded a sensitivity of 87%, specificity of 89%, and overreferral and underreferral rates of 12%. By viewing motor development as a ratio, one is able to forecast motor delay.