Lurton—A Study of Retarded Children. 279 
that all children enter school, or should enter school, at a given 
age, that prescribed by law, spend a year in a grade and then 
pass on into the next. That expresses the very meaning of 
the term grade, i. e. a year of prescribed school work. This 
method is easy of application, regardless of the records kept or 
even if no records at all are kept. All the children in each 
grade are present and can answer, on inquiry, as to their own 
ages. Or parents, especially in case of the very young, can 
easily be consulted. 
Retardation as defined by Ayres. 
“During the past few years the term “retarded” has been ap¬ 
plied with increasing uniformity to describe the condition of 
school children who are too old for their grades. It describes 
but it does not attempt to explain. It is applied to all chil¬ 
dren of this class whatever may be the cause or causes which ac¬ 
count for the fact that they are above the normal age for their 
grades. They may have entered school late, or they may have 
made slow progress ; under both circumstances they are termed 
‘retarded.’ 
“How many able educators and among them some of the 
keenest thinkers in the profession, have taken issue squarely 
with those who use the term in this way and have argued that 
the proper criterion for judging backwardness among school 
children is not age in grade but rather rate of progress. 
“Here we have two criteria, one setting up an arbitrary 
standard which says that the boy who is eight years of age or 
older in the first grade, nine years old or older in the second 
grade, etc., is “retarded” and the other claiming that the 
child who takes more than one year to complete the work of 
one grade is retarded. 
“The criterion which judges the extent of retardation in a 
school system by telling how many of the children are too old 
for their grades has won its way into nearly universal use be¬ 
cause it gives the quickest, clearest, and most easily understood 
answers to these questions. To discover how many over-age 
children are in his school system a superintendent has only to 
