Table 1 Criteria used to assess the quality of papers included in full paper review

Criterion 1: Research question

Paper is based on a clearly defined research question, which is clearly discussed and referenced throughout the paper.

Criterion 2: Internal Validity

The study design was appropriate for the research question and stated study objectives. Selection bias has been minimised; confounding factors have been identified and/or controlled; explanatory variables are based on sound scientific principles; outcome measures are complete and reliable.

Criterion 3 Clarity of Results

Results well described and clear appropriate analytical methods used. The precision of association is given or calculable and is meaningful.

Criterion 4: External Validity

Source population is well described and the eligible population represent the source population. Selected participants represent eligible population and the results are consistent with results from other studies. The study results are generalisable to the source population.

Criterion 5: Strength of Association and Statistical Significance

The study sufficiently powered and precise outcomes have been measured. There are narrow confidence intervals and/or low p-values