Ellis, McDougall and Monk (Dyslexia, 2, 31-58 (1996)) reported data concerning differences of dyslexic, control, poor and precocious readers in regard to reading, spelling, visual processing and phonological processing. They reported that there were no significant differences between the dyslexic children and the other groups in reading, spelling and phonological tasks. The dyslexics were faster in visual processing and had superior comprehension compared with the control and precocious readers. Their study triggered a controversy in regard to the actual academic differences between dyslexic and other children. The purpose of the present paper is to provide an alternative explanation for the lack of significant mean differences between the children with dyslexia and the comparison groups. Responsible for the finding of no significant differences was considered lack of statistical power. An analysis of a sample of data pertaining to spelling differences indicated that for most of the student comparisons there was a very low probability of revealing significant effects (the probability ranged between 1% and 63%, much lower than acceptable levels). Moreover, what was considered more important was the magnitude of the difference between groups (effect size). The standard difference between the groups ranged between 0.12 and 0.64. For five out of the six comparisons the difference between groups was less than 0.5, which is considered to be small for offering any practically meaningful differences between groups (Cohen, Psychological Bulletin, 112, 155-159 (1992)). The issue of actual differences among dyslexic, control, poor and precocious readers needs to be reconsidered using estimates of effect size in order to identify dyslexics' possible deficits in specific academic areas.