Understanding the Comparison, Variation, and Discrepancy Tables


Riverside ScoreTM includes two scores for use in interpreting the presence and severity of any comparison, variation, or discrepancy (i.e., the Discrepancy PR and Discrepancy SD). Detailed information about these scores can be found in the Scores and Interpretation Chapter of your Examiner’s Manual. 


By default, the online scoring platform will be set to run various comparison and variation procedures.


Variations


Variations are procedures that analyze variability in an individual’s performance within the cognitive, oral language or achievement domains to identify a pattern of strengths and weaknesses.


Table

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Comparisons


Comparisons are procedures that analyze if a student’s performance is discrepant from a predictor. In the example below, specific intellectual abilities (COG Tests 1-7) are being used to generate the “predicted” achievement scores, which are compared to the actual achievement scores the examinee obtained on the WJ IV ACH.


Table

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How to interpret positive difference scores for variations and comparisons

Positive difference scores occur when the examinee’s actual performance is greater than predicted:

In the Variations Table above, the difference for the intra-achievement variation for Word Attack is 14 (126-112; Actual score- Predicted Score). This is a positive difference as the actual performance is greater than the predicted score.

Discrepancy PR for Positive Differences

The Discrepancy PR for Word Attack is 95, which indicates that only 5% of examinees in the examinee’s peer group had the same or larger positive difference on that test.

The interpretation is similar for Clusters. For example, in the same Variations Table, the examinee’s Reading Fluency difference value is 22. This translates to a Discrepancy PR of 99, which indicates that only 1% of examinees in the examinee’s peer group had the same or larger positive difference on that test.

Discrepancy SD for Positive Differences

The Discrepancy SD is the standardized z-score that represents the difference between the examinee’s difference score and their average peers’ difference score (who had the same predictor score). This SD is what is used to determine if the observed difference meets significance. Positive differences that meet significance are labeled as “strengths.” Note that examiners can set the discrepancy cutoff within the scoring platform under “Report Options” for the WJ IV. Note that 1.5 SD’s is the general/default cutoff.

How to interpret negative difference scores for variations and comparisons

A negative difference score occurs when an examinee’s predicted score is greater than their actual performance.

For example, in the comparisons table above, the examinee has a negative difference score in the Mathematics Cluster of -16 (note that negative values have the “-“sign to their left).

Discrepancy PR for Negative Differences

The Discrepancy PR for Mathematics is 4%, which indicates that only 4% of examinees in the examinee’s peer group had the same or larger negative difference on that test. (This suggests this difference is rare when comparing this examinee to their peers.)

Discrepancy SD for Negative Differences

The Discrepancy SD for negative difference scores is the standardized z-score that represents the difference between the examinee’s difference score and their average peers’ difference score (who had the same predictor score). This SD is what is used to determine if the observed difference meets significance. Negative differences that meet significance are labeled as “weakness”. Note that examiners can set the discrepancy cutoff within the scoring platform under “Report Options” for the WJ IV. 1.5 SD’s is the general/default cutoff.