─────────────────────────────┬───────────────────────────────────────── │ Percentages Retarded ─────────────────────────────┼────────────────────┬──────────────────── │ 4 or more grades │ 5 or more grades Cincinnati, Ohio—June 1907 │ 8.8% │ 2.5% Cleveland, Ohio—1909-1910 │ 3.0 │ 0.9 Des Moines, Iowa—1915 │ 1.0 │ 0.2 Memphis, Tenn.—June 1908 │ 6.6 │ 1.5 Minneapolis, Minn.—June 1915 │ 1.3 │ 0.5 Pittsburgh, Pa.—1913 │ 4.7 │ 1.1 Springfield, Mass.—Sept. 1907│ 1.2 │ 0.1 Reading, Pa.—1906-1909 │ 2.2 │ 0.4 ─────────────────────────────┴────────────────────┴──────────────────── The distributions for Cincinnati, Memphis and Springfield are taken from Ayres' Laggards in Our Schools. That for Minneapolis is from unpublished data. That for Reading is from Snyder's Retardation in Reading Public Schools. The others are from Superintendents' reports. By considering only pupils in the public schools who are 12 and 13 years of age, the last years in which practically all are in school, we can get a check upon this method of estimating for delinquent groups. I have compared the age-grade distributions for those of these ages in eight cities showing the percentages retarded 4 or more and 5 or more years. They are given in Table XV. These records indicate that at least five or more years retardation below a standard of age 7 in the first grade for all who are 12 years of age or over might be taken for a low estimate of the frequency of deficiency, and four or more years retardation for a maximum estimate. Except under special circumstances those who are older than 14 years should be considered as if the highest grade attained was at 14 years of age. These borderlines of school retardation for the purpose of estimating the frequency of deficiency check fairly well with estimates for the Minneapolis and other groups of delinquents which have been tested by the Binet scale, as we shall note later in this chapter.