Should extremely low scores be considered deviant?

Answer:  Extremely low scores merely reflect the absence of reported problems.  The profile compresses the low end of the syndrome scales so that a T score of 50 is the minimum obtainable on any scale.  However, nearly all children have at least some problems.  On the CBCL/1.5-5, the mean Total Problems score for non-referred children in our normative sample was 33.3.  On the C-TRF it was 23.1 for boys and 19.6 for girls.  Total Problems scores < 2 were obtained by only 2% of our normative sample on the CBCL/1.5-5.  And Total Problems scores of 0 were obtained by 2% of our normative sample on the C-TRF.  Such low scores suggest that the respondent has not understood the form, is poorly informed about the child or is not being candid.  Total Problems scores o 3 and 4 on the CBCL/1.5-5 are also low enough to be questionable.