Table 1 Results of methodological assessment of studies included in the review

Did the study address a clearly focused issue?

Was/were the study outcome(s) to be measured clearly described?

Were the questions posed to assess outcome(s) clearly defined?

Was the study samle clearly defined?

Were participating schools recruited in an acceptable way?

Were the pupils recruited in an acceptable way? ¹

Were characteristics of subjects at enrolment reported?

Is it clear how data were collected?

Did the authors mention that the instrument used for data collection was pre-tested or validated?

Were the questions posed appropriate to address given outcomes?

Was participation rate reported?

Was participation rate sufficiently high?

Was the data analysis sufficiently rigorous?

Were other factors accounted for that could affect outcomes?²

Were results appropriately reported? ³

Is there a clear statement of findings?