Talking About Impairment
Rees Chapman, Ph.D.
April 2012

A psychologist is reviewing test results with the father of a child he just tested:

PhD:
". . . and your son's full scale IQ is 67."
 
Dad:
"So. . . what does that mean?"
 
PhD:
"Most psychologists say a score of 67 falls more than two standard deviations below average, which they call moderately impaired."
 
Dad:
"Gee, that sounds pretty bad."
 
PhD:
"Actually, the psychiatric diagnostic manual only calls it mild mental retardation."
 
Dad:
"Oh. . . so it's really only mild.  That's not so bad.. . ."
 
PhD:
"Yes, but if you were trying to get disability benefits for your son, the adjudicator would call his impaired IQ marked."
 
Dad:
"Marked?  Is that good, or bad?"
 
PhD:
"Well, they also call any deficits which cause more than minimal functional limitations severe."
 
Dad:
"Uh. . . what?"
 
PhD:
" But, the creator of the intelligence test would call an IQ of 67 extremely low."
 
Dad:
"Extremely low?  That's terrible.  I mean, isn't it?  How can the same score be mild, and moderate, and marked, and severe, and extreme?  This is ridiculous.  It sounds like the system was created by imbeciles.  Or morons.  Or idiots."

Social Security criteria for degrees of impairment do not correspond with those used by most psychologists. According to Disability Adjudication Section (DAS) documentation, marked limitation is defined as what "could be expected to be found on standardized tests with scores that are at least two, but less than three, standard deviations below the mean. . ."*  This contrasts with psychometric criteria which generally define such impairments as moderate. As well, DAS criteria for extreme are said to apply to test results "that are at least three standard deviations below the mean," which are generally interpreted by psychologists as severe.

So, I'm asked to rate a child's Concentration, Persistence and Pace.   The tests' standard scores are all in the sixties, so I rate impairments as moderate.  The DAS reviewer of my report, using a different criteria and looking for marked or extreme impairments, assumes I do not regard the child's ADHD as functionally incapacitating.   Benefits are denied, even though deficits are indeed disabling.

When psychologists and adjudicators (and diagnosticians and test creators) don't use the same terminology, a great many disabled persons "slip through the cracks."

*20 CFR 416.926a(e)
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