TY - JOUR
T1 - Bias and error rates for premorbid IQ estimators
T2 - Comment on Veiel and Koopman (2001)
AU - Grove, W. M.
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2001
Y1 - 2001
N2 - H. O. F. Veiel and R. F. Koopman (2001) advance statistical and legal theses. They correctly point out that the usual regression formula for estimating a pre-event IQ underestimates high IQs and overestimates low IQs (due to regression to the mean). They call this a conditional bias and show it can be sizeable. The author takes issue with their claim that a new estimator they propose should be used in place of the usual formulas, because it negates this statistical bias. Their argument against the usual estimator conflates statistical bias and legal bias. Their discussion in favor of their new estimator mentions, but does not derive a general formula for, a gross loss of precision entailed by use of the new estimator. The author quantifies this loss of precision and, using Veiel and Koopman's numerical example, shows that their estimator quadruples error.
AB - H. O. F. Veiel and R. F. Koopman (2001) advance statistical and legal theses. They correctly point out that the usual regression formula for estimating a pre-event IQ underestimates high IQs and overestimates low IQs (due to regression to the mean). They call this a conditional bias and show it can be sizeable. The author takes issue with their claim that a new estimator they propose should be used in place of the usual formulas, because it negates this statistical bias. Their argument against the usual estimator conflates statistical bias and legal bias. Their discussion in favor of their new estimator mentions, but does not derive a general formula for, a gross loss of precision entailed by use of the new estimator. The author quantifies this loss of precision and, using Veiel and Koopman's numerical example, shows that their estimator quadruples error.
UR - http://www.scopus.com/inward/record.url?scp=0034870361&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034870361&partnerID=8YFLogxK
U2 - 10.1037/1040-3590.13.3.396
DO - 10.1037/1040-3590.13.3.396
M3 - Short survey
C2 - 11556276
AN - SCOPUS:0034870361
VL - 13
SP - 396
EP - 398
JO - Psychological Assessment
JF - Psychological Assessment
SN - 1040-3590
IS - 3
ER -