Estimating the Size of Vocabularies of Children and Adults
ONE OF THE oldest problems in educational research has been the estimation of vocabulary size of children and adults. Estimates for the same age groups vary considerably; some of the more re cent studies report more than ten times the vocabu lary size estimated by earlier studies. Thus, while Terman (38) estimated an average vocabulary of 3,600 words for third graders, M. K. Smith (36) es timated a total of 44,000 words. For first g r ade children, the variations are equally discrepant; Madorah E. Smith (35) estimated a total of 2, 562 words; Dolch (12), a total of 2,703; M. K. Smith 24,000;and Shibles (34), a total of 26, 000. For uni versity undergraduates, we find even greater dis crepancies: from about 19,000 words reported by Kirkpatrick (21, 22) and Doran (13)to 157, 000 by Sea shore and Eckerson (30) and over 200,000 by Hart mann (18,19). What are the possible reasons for such var i a tions ? One explanation may be that there has been an improvement in education and in early stimula tion through TV, 2 and hence that children now know more words. Another may be that the variations are related to the procedures used in estimating vocabulary size. The extent of the variations in a fairly small time span suggests that improved edu cation and stimulation alone cannot account for the later and higher estimates, implying essentially that methodological issues are involved.