Table 2.

Questions used to assess scientific quality of the study and the reader's ability to adequately understand the intervention

Questions	Trials with Comparison Groups	Trials with evaluation before & after	Observational
Is the strategy defined?	Yes	Yes	Yes
Is there a methods section?	Yes	Yes	Yes
Are the strategy and methods sections defined in a comprehensive way?	Yes	Yes	Yes
Is the study question clearly defined?	Yes	Yes	No
Are outcomes/outputs clearly defined?	Yes	Yes	No
Can outcomes be attributed to interventions?	Yes	Yes	No
Is the explanation of the target population sufficient?	Yes	Yes	Yes
Is the target population studied appropriate?	Yes	Yes	No
Was the method used to obtain cases and controls explained?	Yes	No	No
Was randomization used to select cases and controls?	Yes	No	No
Was the method of selecting cases and controls appropriate?	Yes	No	No
Was a method for checking immunization status described?	Yes	Yes	Yes
Was the method for determining sample size provided?	Yes	Yes	No
Have confounders been identified?	Yes	Yes	No
Were the confounders taken into consideration?	Yes	Yes	No
Was the time frame of the study defined?	Yes	Yes	No
Is the time frame sufficient for the intervention to have an impact?	Yes	Yes	Yes
Did the authors make comments regarding limitations of the strategy?	Yes	Yes	Yes
Did the authors compare results with similar studies?	Yes	Yes	Yes
Was adequate data analysis conducted?	Yes	Yes	Yes
Was the response rate adequate?	No	Yes	No