Table 4.

Interpreting change based on the natural distribution of Week 2–Week 1 difference scores.

	10%	15%	20%	Normal Variability	20%	15%	10%
Reaction Time (ms)	71.60	59.90	53.20	53.20−23.20	−23.20	−31.10	−41.70
Reaction Time (SWAY)	−11.93	−9.30	−8.33	−8.33–4.29	4.29	5.14	6.82
Impulse Control (ms)	57.40	43.60	36.90	36.90–−31.70	−31.70	−39.10	−49.00
Impulse Control (SWAY)	−7.19	−4.93	−4.37	−4.37–3.48	3.48	4.48	6.69
Inspection Time (ms)	54.40	42.50	25.50	25.50–−23.80	-23.80	−25.50	−37.40
Inspection Time (SWAY)	−8.00	−6.25	−3.75	−3.75–3.50	3.50	3.75	5.50
Working Memory (SWAY)	−9.40	−7.30	−6.00	−6.00–9.00	9.00	11.10	13.90

ms, milliseconds. The difference scores in this table were derived by subtracting the Week 1 scores from the Week 2 scores. The 10% score refers to the difference score that occurs in 10% or fewer of the total samples, and the 20% difference score refers to the difference score that occurs in 20% or fewer of the total sample. Normal variability represents the range of difference scores obtained by 60% of the sample. For example, a difference score of −41.70 on the Reaction Time (ms) test represents improved performance that is seen in 10% or fewer of the sample. A difference score of 36.90 on the Impulse Control (ms) test represents a decline in performance that is seen in 20% or fewer of the sample. For Working Memory (SWAY), Reaction Time (SWAY), Inspection Time (SWAY), and Impulse Control (SWAY), higher scores denote better performance. For Reaction Time (ms), Inspection Time (ms), and Impulse Control (ms), higher scores denote worse performance.