The psychometric results support the use of the SDS subscales (items 1-3) and total score (sum of items 1-3) in an ADHD population.
*Each item has 4 score levels ranging from 0 (worst) to 3 (best); each LCI score (basic, advanced and total) is the sum of item scores The mean total score was 28.5 (SD 12.5, median 33), the mean basic score was 17.1 (SD 5.5, median 21) and the mean advanced score 11.3 (SD 7.8, median 12).
The HSCL total score is the sum of items divided by the number of items answered.
We added the total correct answers for each child and divided this sum by the total number of items answered, yielding a percentage correct score.
The scores from each category were added to form three scores: inattentive score (sum of items 1 to 9), hyperactive/impulsive score (sum of items 10 to 18) and total score (sum of items 1 to 18).
The total and all subscale scores are summed and divided by the total number of items in the total and subscales.
GSI score was calculated using the sums of the nine symptom dimensions plus the seven additional items not included in any of the dimension scores, and dividing those sums by the total number of items to which the individual responded.
In each table, counts sum to more than the total number of items as individual stories often feature more than one region or disease/health condition classification.
The procedure we used was the following: first, the "don't know" responses were noted in a non-numerical manner, by using asterisks to indicate missing values and these values were counted as 0; secondly, the response scores were added up and the sum was divided by the total number of items within the subscale in that age period for which there were numerical scores.
Three scoring options for combining item responses in the final model were evaluated: 1) total sum of item responses, 2) dichotomous variable for each item, and 3) weighted sum of item responses.
Subscale scores (range 4 20) are calculated as the sum of item ratings and a total fatigue score (range 20 100) is calculated as the sum of subscale scores.
