TABLE 7-2 Comparison of Classification as MR, LD, and Ineligible Using FSIQ and PIQ to Estimate Aptitude by Ethnic Group

 

PIQ Classification

 

 

FSIQ Classification

MR

Ineligible

LD

TOTAL

Kappa

White

MR

7

1

2

10

 

Ineligible

3

15

6

24

 

LD

1

0

20

21

 

Total

11

16

28

55

0.63

Black

MR

10

4

0

14

 

Ineligible

0

16

2

18

 

LD

0

0

10

10

 

Total

10

20

12

42

0.78

Hispanic

MR

7

7

5

19

 

Ineligible

1

6

11

18

 

LD

0

1

15

16

 

Total

8

14

31

53

0.31

There is somewhat of a paradox in this classification exercise. While the use of performance IQ as the estimate of aptitude reduced the number of Hispanic students qualifying as MMR by 11, it also resulted in increasing the number of Hispanic students qualifying as LD by a total of 16. By optimizing the aptitude estimate while the measure of achievement remained constant, the total number of LD cases for Hispanics more than offset the reduction in the number of children who moved out of the MR classification.

The construct of intelligence has historically been fundamental to defining MR. As discussed elsewhere in this report, tests of intelligence have very limited curricular validity and, when routinely administered to establish the eligibility of students as MR or LD, add considerably to the cost of assessment. Nevertheless, in the context of MR, “subaverage general intelligence” is a defining feature of the disability and using measures other than tests of intelligence or resistance to treatment as criteria for eligibility raises some perplexing possibilities. For students who are referred for psycho-educational assessment, the charge is to identify those cases whose “failure to thrive” in the best clinical judgment of the individual education program (IEP) committee is “due to low general intelligence” as opposed to competing hypotheses, such as a specific processing problem (i.e., LD) or emo-



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