Learning disability testing methodology
Article © Nancy Cowardin, Ph.D.; used with permission.
Nancy Cowardin, Ph.D.
For additional information, please contact Nancy Cowardin at [email protected].
Formal assessment for Learning Disabilities requires standardized educational
tests in four functional areas: Intelligence, Academic Achievement, Language
and Information Processing. Of course, all testing must adhere to administration
guidelines published in accompanying clinician's manuals.
An IQ test must be administered to rule out mental retardation and to
procure a score for IQ-achievement comparisons in academic subjects. This
test must utilize 15 point standard deviations and yield a mean of 100
(the statistical population mean). Where cultural or language differences
prohibit fair assessment of verbal intelligence, a nonverbal test may
be used for score comparison purposes.
Achievement testing requires a complete battery focused on three academic
areas: reading, mathematics, and written language (spelling). Reading
may further be broken down into the two subareas of decoding individual
words and comprehending text. Similarly, math may be split into subskills
of computation and practical application in daily circumstances. The spelling
test that I use requires subjects to self-produce written language (as
opposed to simply choosing the correct word from several provided) as
words are dictated. All academic subtests yield standard scores which
are used in the IQ - achievement comparison formula. Here a "significant"
discrepancy is translated to mean that achievement falls 22 points (or
more) below the IQ (expected) level.
For most people, information is received, processed, recalled, and expressed
using the two basic modalities of vision and hearing. Thus, both modalities
require assessment to ascertain whether deficits in these basic processes
are responsible for observed IQ-achievement discrepancies. Testing in
this area may be taken from one battery (learning aptitude) or may utilize
several independent tests knows to measure particular subskills within
modalities. Either combination of tests should focus on auditory or visual
attention, encoding of information, organization and processing, memory
and retrieval, and expression. It is helpful if these tests yield mental
age scores which can then characterize the magnitude of age-discrepancies
in subprocesses and modalities.
Language-based Learning Disabilities is a common occurrence, especially
where reading and written language are deficit areas, thus most assessors
look at receptive versus expressive language capabilities in test subjects.
I prefer to use simple vocabulary measures to compare these language subareas
as well as to exact yet another composite measure of mental age in clients.
This can also guide further testing in social maturity or moral development,
both language-based skills, if needed for a more complete developmental
Educational professionals are ethically bound to maximize the potential
of tested students/clients wherever possible. This requires determination
of the client's physical status, health, and willingness to participate
in the assessment process. Also, differential testing standards may be
applied where, in the assessors' judgment, standard procedures would tend
to depress scores prejudicially. For example, rewording of test items
in non-language areas (e.g., mathematics problems) is allowable to prevent
language deficits from compounding scoring in these problem-solving processes.
It is my intention to elicit the best possible effort from clients in
all test areas. On an ongoing basis, I observe the client's body language
and note verbal indications of "struggle behavior" in difficult
test areas. Generally, this behavior should be observed to increase as
test content becomes more difficult. Additionally, I watch for failure
to try, apathy or malingering, if present, and note these behaviors in
my final report. If a client's effort varies widely across tests, I note
so in the report as well. Finally, I control for malingering by presenting
clients with four test batteries which contain some duplicate items over
the several-hour process. This enables the clinician to check for error
consistency and/or error correction during testing. For example, it is
possible for a subject to recall an item receptively (when presented to
him with several other items) which he did not know expressively (self-produced),
but the reverse is not typical.
Finally, each assessor's test battery is personally chosen according
to his or her experience and comfort with the procedures. Tests chosen
by another professional may differ from my own, but both batteries should,
at the very least, produce information useful in the IQ-achievement discrepancy
formula plus supporting information processing data which describes observed