ntervention, Maintenance, and
Generalization Effects
Based on Scruggs and Mastropieri’s (1998) recommendations
for interpreting the magnitude of PND scores, as noted
earlier, the results indicated that social skills interventions
produce low to questionable treatment and generalization effects
and moderate maintenance effects for children with
ASD. The results indicated a questionable intervention effect
for the studies in the meta-analysis (n = 52; PND M = 70%,
range = 17–100%). Just over half of the reviewed studies
(52%) produced mean intervention PND scores above 70.
Three studies did not provide individual data points for the
intervention phase of the studies; therefore, intervention PND
was not calculated for these studies. Maintenance effects
were reported in 25 studies, and generalization was reported
and graphed in 15 studies. The results indicated moderate
maintenance effects (n = 25; PND M = 80%, range = 17–
100%) and low generalization effects (n = 15; PND M = 53%,
range = 17–100%).