5. Risk of bias ‐ Isaac 2005.

Domain	Authors' judgement	Support for judgement
Bias due to confounding	Moderate risk	The study did not take into account the possibility of potential confounding effects as a result of media publicity which could have promoted the jump site
Bias in selection of participants/data	Low risk	The study assessed interventions that were aimed at the general population, therefore all individuals who would have been eligible to take part in the study were included
Bias in classification of interventions	Low risk	Intervention status is well defined
Bias due to deviations from intended interventions	Low risk	There were no deviations from the intended interventions that were likely to impact on the outcome
Bias due to missing data	Low risk	Data were reasonably complete
Bias in measurement of outcomes	Low risk	The methods of outcome assessment were comparable across intervention periods
Bias in selection of reported result	Unclear risk	No access to study protocols for this study therefore it is difficult to assess this domain

Low risk of bias: the study is comparable to a well‐performed randomised trial with regard to this domain.
 Moderate risk of bias: the study is sound for a non‐randomised study with regard to this domain but cannot be considered comparable to a well‐performed randomised trial.
 Unclear risk of bias: too few details are available to make a judgement of ‘critical’, 'serious', 'moderate', or ‘low’ risk