Table 3 Critical appraisal criteria

Internal validity

Clear and repeatable methodology

Whether the methodology described to assess the effectiveness of the intervention is clear and repeatable. I.e. Is the minimum amount of information reported for another party to be able to replicate the methodology used

Methodology is appropriate to the assessment of effectiveness

Whether the methodology described to assess the effectiveness of the intervention is suitable. I.e. If the methodology attempted to assess behaviour changes in relation to an intervention are measures of behaviour change described in the methodology?

Reported findings consistent with the methodology employed

Whether the results reported in the document are consistent with the methodology described. I.e. If the methodology stated that behaviour changes in relation to the intervention were assessed are behaviour changes reported?

Confounding factors are taken into account

Whether the study reports or discusses how results of the assessment may have been influenced by the presence of another variable (whether measured or not)

Sample size is specified

Whether the study reports the sample size assessed in relation to the intervention. I.e. If household surveys were described in the methodology are the number of households surveyed reported?

External validity

Sample frame is specified

Whether the sample frame is specified. Specifically, whether the number of people sampled is reported in relation to the total number of people for which the intervention was applied