An objective of future surveys could therefore be to put greater emphasis on seeking input regarding issues that are not raised in the survey, e.g. by inviting respondents to identify unaddressed issues, suggest research topics and propose solutions. Finally, we note that the survey can be an important source of insight regarding the potential gap that may exist between expert beliefs regarding the most effective measures and the existing evidence regarding these measures. Identifying any such gaps could shed light on the need to generate more evidence in certain areas, or alternatively, to better disseminate existing evidence.