One way of demonstrating the conservative
nature of these analyses is illustrated in a longitudinal
study that we have conducted
(Cipielewski & Stanovich, 1992). We addressed
the question of whether reading volume can
predict individual differences in growth in reading
comprehension from third grade to fifth
grade. We found that reading volume predicted
variance in fifth-grade reading comprehension
ability after third-grade reading comprehension
scores had been removed. Thus, in removing
the contribution of reading comprehension in
our adult studies, we are undoubtedly removing
some of the variance in variables such as vocabulary
and general knowledge that is rightfully
attributed to reading volume.