“…Cochrane Database of Systematic Reviews of these four aspects may be a ected by child-related variables, such as age, level of functioning, motivation, concentration and attention; system-level constraints, such as the available economic and human resources; and intervention-related aspects, such as desired outcomes (Zeng 2012). Results from di erent clinical samples, however, suggest that dosage intensity is an important predictor of the intervention e ect, indicating that a high frequency is better than a low frequency .…”