T-scores were developed to facilitate the interpretation of test results by enabling the comparison of a young person's score against norms from a representative normative sample. A T-score is a standardized score that is calculated from the total distribution of scores within the community sample. Scores are rescaled so that T-scores have a mean of 50 and a standard deviation of 10. Scores within one standard deviation (ie. a T-score of 10) above the mean on any dimension are regarded as being within the normal range on that dimension. This process ensures that all subscales and the total score can be interpreted along the same scale, with the same mean and standard deviation, even though they initially had different numbers of items and different non-transformed means.
A T-score of 10 points above the mean of 50 (ie. T-score of 60) represents a value of 1 standard deviation above the mean and is indicative of sub-clinical anxiety. As the PAS should not be used as a diagnostic instrument, in the absence of a clinical interview, we suggest using a T-score of 60 as an indicator of sub-clinical or elevated levels of anxiety. This justifies further investigation and confirmation of diagnostic status using clinical interview. Some clinicians prefer to use a criterion of a T-score of 65, reflecting clinical status (or 1.5 standard deviations above the mean). However, given that the PAS is not intended as a clinical instrument when used in isolation, this is not recommended.
Given that the PAS assesses several domains of anxiety, it is important for clinicians to examine both the Subscale scores and the Total Score. It is possible for a young person to show a T-score of 60 or more on one subscale and yet still be within the normal range on the Total Score. Please remember that the PAS is not a clinical diagnostic instrument and it is developed to be used in combination with a clinical interview, or as a screen for children with elevated symptoms.