Stand ford-Binet Test has six items of varied content assigned to each year, each item when passed earning a score of two months of mental age.
The procedure for testing is first to establish the child’s basal mental age, the mental-age level at which he passes all items. Two months of mental age are then added for each item passed at higher age levels. Consider, for example, the child who passes all items at the mental-age level of six years.
If the child then passes two items at the seven-year level, four months are added; passing an additional item at the eight-year level adds two more months. This particular child will have an earned mental age of six years and six months, regardless of chronological age. The test allows for some unevenness in develop- so that two children can earn the same mental age by passing different items on the test.