30 Indiana University Studies 



marily because it appears to be more generally used and 

 hence more data are available for comparative purposes. The 

 reader should bear in mind that the amounts of retardation 

 and acceleration given in the following are computed by this 

 method and not actual. 



The Computed Quantities Represent Overage and Under- 

 age rather than Retardation and Acceleration. Strictly speak- 

 ing, these quantities do not represent retardation and acceler- 

 ation but overage and underage. They are, however, gen- 

 erally spoken of as representing the former. Thus, a sig- 

 nificant distinction is lost sight of. If an age-grade table 

 is studied with respect to the grouping of children for in- 

 structional purposes, one is primarily concerned with the 

 homogeneity of the grade groups, for it is assumed that the 

 more nearly alike the members of the group are the more 

 favorable the conditions are for teaching. One character- 

 istic of children is their chronological ages. When a grade 

 group is made up of children of widely different chronological 

 ages as is the case in Tables I to VI, the groups lack homo- 

 geneity in that respect and thus the most favorable condi- 

 tions for instruction do not exist. Some have gone so far 

 as to state that the age of a child is more important from 

 this point of view than the number of years he has spent in 

 school.' That from the instructional point of view there is 

 some truth in this assertion one cannot deny. However, the 

 mental age of a child frequently does not agree with his 

 chronological age and it is the former factor rather than the 

 latter which produces the non-homogeneity of the groups in 

 ability to learn. Thus, from the instructional point of view 

 the overage and underage of pupils have a certain significance. 

 Their computation from age-grade tables is definite when we 

 have defined the age or ages for the several grades. 



From the point of view of the economical organization of 

 the school, one is primarily interested in the progress of the 

 pupils, i.e. the per cent who are promoted regularly, the per 

 cent who fail, and the per cent who are permitted to skip a 

 grade. Repeating the work of a grade or a half-grade rep- 

 resents a financial loss to the school and a time loss to the 

 child. Thus, the per cent of retardation has been called a 

 measure of the efficiency of a school system. 



' Ayres, L. P. Laggards in Our Schools, pp. 39-42. 



