JOMPARABILITY
OF
THE WISC AND THE WISC-R IN NORMAL
CHILDREN OF DIVERGENT SOCIOECONOMIC BACKGROUNDS
JUNE
M.
TUMA,
ALAN
S.
APPELBAUM,
AND
DAVID
E.
BEE
The University
of
Texas Medical Branch at Galveston
WISC and WISC-R IQs of two groups of normal ten-year-old children from
divergent socioeconomic backgrounds
(N
=
36)
were compared in a counter-
balanced research design. Generally, all WISC mean IQs were higher than the
WISCR mean IQs for both grou
s
of children. Significantly higher WISC IQs
were obtained on the Verbal andPFull Scales of the low socioeconomic group
and on the Performance and Full Scales
of
the high socioeconomic group.
Correlat,ions between tests for Verbal, Performance, and Full Scale IQs were
.95,
.79,
and
.91
for the low socioeconomic group, and
.84,
57,
and
.87
for the
hgh socioeconomic group. Although practice effects did not appear to signifi-
cantly affect IQs of the low socioeconomic yp, various practice effects were
observed in the high socioeconomic group. egative effects were observed for
both WISC and WISC-R on the Verbal Scale, whereas positive effects were
observed on both Performance and Full Scales in this group. Analysis of simple
effects reveals that WISC and WISC-R IQs did not differ significantly upon
first administration, but were significantly different upon second administra-
tion. Conclusions were drawn that while WISCR yields
a
lower IQ estimate
than WISC for children
of
lower ability, results were not
so
clear for the
children of iligher ability, due to practice effects which disproportionately
favor increases on WISC IQs
upon
second administration. The greater prac-
tice effects found on the WISC have implications for comparisons of the two
tests in counterbalanced research designs. Simple randomized or treatment-
by-levels design may be more useful in comparisons of the WISC and the
WISC-R because of the bias introduced by counterbalanced designs.
A few reports of comparisons of the WISC and the WISC-R IQs have recently
appeared in the literature. Most investigators used abnormal, primarily below-
average
I&
children, although one study (Schwarting,
1976)
used average school
children. Fairly consistent results indicate that the WISC-R yields lower IQs
than
the WISC.
A finding which may affect interpretation of the comparability of the WISC
and WISC-R is
a
differential practice effect of the two instruments in
a
counter-
balanced design (Klinge, Rodziewicz,
&
Schwartz,
1976).
The extent to which this
variable affects the results
of
those studies which utilized
a
counterbalanced design
(Berry
&
Sherrets,
1976;
Hamm, Wheeler, McCallum, Herrin, Hunter,
&
Catoe,
1976)
is
unknown. Until these transfer
of
learning effects are understood, the
degree of WISC and WISC-R IQ comparabilitv is unclear.
The primary purpose of the present study
is
to determine
if
the WISC and the
WISC-R yield comparable IQ estimates in normal children within both high and
low socioeconomic groups. A secondary purpose is to examine effects
of
repeated
administration of similar instruments.
METHOD
Subjects
Test-retest comparisons were obtained on
36 (18
male,
18
female) normal
white children' from a metropolitan school district. Rather than introduce another
'Written consent forms were obtained from both guardian (parent
or
legal guardian) and child
according
to
standards set forth by the University
of
Texas Medical Branch Human Research Com-
mittee.
Requests for reprints should be sent to June
M.
Tuma, Division of Child
&
Adolescent Psychiatry,
University of Texas Medical Branch, Galveston,
TX
77550.
339