
Difference between Terra Nova and IQ tests
By Inderbir Kaur Sandhu, Ph.D
Q:
I just received by son's 7th grade Terra Nova tests, his
Total Score was 91 and the IQ component of this test was
122. How does the IQ test on the Terra Nova compare to other
IQ tests, such as the Wechsler Intelligence Scale for
Children (WISC)? I don't know how to interpret these scores.
Any insight would be helpful. Thank you.
A: The major difference here is
that the Terra Nova is an achievement test whereas IQ tests
(such as the Wechsler's and the Stanford-Binet) are
ability/aptitude tests. This does not warrant a one-to-one
comparison.
In principle, achievement tests are more directly concerned
with what is taught is schools, which is not the case with
ability tests. Most achievement tests items resemble closely
to the knowledge and skills taught at school. As for ability
tests, the skills tested may not be school based with less
reliance to specific knowledge (e.g., analogical thinking,
although essential for success, is not something that is
taught at school). This is why students who score lower on
an achievement test than on an ability test may be regarded
as underachieving. However, this is not true as there is no
single test to measure potential in general and perhaps a
combination of different tests may be better to determine
the potential of a student.
Furthermore, on ability tests, there are clear cut tests of
nonverbal skills which may not be as important or sometimes
on-existent on achievement tests. Therefore, students who
may have scored very high on nonverbal tests but much, lower
on verbal and quantitative parts of an ability test may be
perceptually oriented, but this may not be regarded highly
in school as school-based subjects are mostly about symbols,
that are numbers and letters. There is hardly any room for
those who are perceptually oriented. Such a student may be
seen as underachieving at school.
The Terra Nova tests compare students with others in their
grades around the nation. Hence, the scores are listed in
percentiles, as in your case. It also includes a component
that acts like an IQ test. This component measures the
students' ability to use information and apply it to new and
different situations. It also gauges how a student analyzes
and employs higher-level thinking skills. But, do bear in
mind that this is a very rough measure of intelligence.
In reality, these tests are just snapshots of a student's
performance. To get a better and more detailed picture, you
should ask the teachers if your son's test scores are
indicative of classroom performance. To get his IQ measured,
you would need to see a qualified educational psychologist
who would also be able to interpret the scores and perhaps
explain areas of strength and weakness by looking at both
the IQ and Terra Nova test scores.
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