Participants in the study. The participants were students with identified
learning disabilities. A study with students without learning disabilities was
included only if one of the following criteria was met: (a) separate outcome data
were presented for the different participant groups so that effect sizes could be
computed separately for students with LD; or (b) if separate outcome data
were not presented for students with LD, then over 50% of the study
participants needed to be students with LD.
All studies provided operational definitions