In this discussion of quantitative research synthesis (meta-analysis), past
criticisms of meta-analysis are reviewed along with the ways in which they
have been addressed. The problems associated with synthesizing single-subj
ect research are discussed, particularly the difficulties in obtaining a me
tric equivalent to the effect size calculated for group-design research. Af
ter analyzing recommended approaches, the authors endorse the percentage-of
-nonoverlapping-data metric. Their earlier single-subject synthesis showing
limited efficacy for social skills instruction is then reviewed. The findi
ngs are discussed in relation to the nature of single-subject research, the
proper role of research integration, and the influence of subjectivity in
interpreting research findings. Finally, possible reasons for disappointing
findings regarding the effectiveness of social skills instruction are expl
ored. The authors conclude that, until expressed concerns are remedied, it
is neither incorrect nor illogical to question the efficacy of social skill
s instruction.