title: On estimating processing variance: commentary and reanalysis of Kail's "Developmental functions for speeds of cognitive processes".
abstract: A recent paper by Kail (1988) in this journal appears to contain a significant error in the data analysis. The "goodness-of-fit" coefficients reported which suggest that overall about 94% of the variance can be accounted for by the model seem to be a substantial overestimation as a result of inappropriate procedures for statistical modeling. Using the data made available to us by Kail, we have reanalyzed these results. The corrected values range from 0.9 to 92.1% for the individual tasks with an overall average between 40 and 60%. We suggest that the support for the original conclusions is considerably weaker than reported.
authors.affiliation: Department of Psychology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: G R
authors.initials: GR
authors.lastname: Morrison
authors.forename: S R
authors.initials: SR
authors.lastname: Morrison
authors.forename: D P
authors.initials: DP
authors.lastname: Keating
mesh_terms: D001076:Aptitude; D001288:Attention; D002648:Child; D002657:Child Development; D003071:Cognition; D006801:Humans; D007206:Individuality; D015233:Models, Statistical; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011930:Reaction Time