Data from over 3400 individuals ranging from 5 to 93 years of age were analyzed to investigate the structural organization of cognitive variables, and to use that structure to examine relations between cognitive abilities and neuropsychological variables. The results indicated that the variables could be organized into the same cognitive ability factors in both children and adults, and that in both segments of the lifespan a large proportion of the age-related influences on measures of cognitive functioning was shared across different cognitive abilities. Another set of analyses revealed that many neuropsychological variables were closely related to established cognitive abilities, although the pattern of influences varied somewhat across different age groups. Finally, variables assumed to reflect executive functioning were found to lack construct validity because there was nearly perfect overlap of the individual differences in what these variables had in common and a construct of fluid intelligence.