Table 2.

Quality evaluation of selected investigations (adapted from Haynes et al [8])

Study Characteristic	Evaluation Criteria	Scoring*
Study Design	1. Randomized trial 2. Non-randomized trial with control group 3. Descriptive/cohort study	3 points 2 points 1 point
Selection and specification of the study sample	1. Random selection with description of 4 to 5 demographic variables 2. Random sampling without sufficient description of the demographic variables 3. Convenience sampling with sufficient background information 4. Bonus point for a description of how many patients were excluded and reasons for exclusion.	3 points 2 points 1 point + 1 point
Specification of the illness/condition	1. Illness specified with reproducible inclusion/exclusion criteria. 2. Diagnostic criteria only were provided 3. Diagnosis only 4. Bonus point if all prior criteria were met and co-morbidities were described.	3 points 2 points 1 point +1 point
Reproducibility of the study	1. Description permits the reader to replicate the study 2. Results provided a standard for computing effect size (i.e., variable means, standard error, or standard deviation correctly stated).	1 point Yes: 3 points No: 0 points
Outcomes specification and measurement	1. Outcome measure is described and valid instrument use was clearly provided 2. Outcomes were not measured using valid and reliable instruments 3. Results did not match the described outcomes to be measured in the study	3 points 2 points -1 point
Maximum score		18 points

^* Only studies that scored 12 or higher were retained for meta-analysis