We do not provide qualitative descriptors for the subtest scores in the manuals, and it is not recommended to use the composite descriptors for the subtests because the range of scores differs too much.

Other references do provide qualitative descriptors for subtests that are based on the standard deviations.
Sattler & Dumont (2004) suggest the following on page 115 of Assessment of Children: WISC-IV and WPPSI-III Supplement.:

For three categories of descriptors:

• Scaled score from 1-7 is described as a weakness or below average with a corresponding percentile rank of 1-16.
• Scaled score from 8-12 is described as average with a corresponding percentile rank of 25-75.
• Scaled score of 13-19 is described as a strength or above average with a corresponding percentile rank of 84-99. (page 115, Table 4-1).

For five categories of descriptors:

• Scaled score from 1-4 is described as exceptional weakness, very poorly developed, or far below average with a corresponding percentile rank of 1-2.
• Scaled score from 5-7 is described as weakness, poorly developed, or below average with a corresponding percentile rank of 5-16.
• Scaled score from 8-12 is described as average with a corresponding percentile rank of 25-75.
• Scaled score from 13-15 is described as strength, well developed, or above average with a corresponding percentile rank of 84-95.
• Scaled score from 16-19 is described as exceptional strength, very well developed, or superior with a corresponding percentile rank of 98-99.