Date	Event	Description
30 August 2012	New citation required but conclusions have not changed	The evidence base remains weak and results are largely unchanged from previous version.
22 August 2012	New search has been performed	Update search was performed from January 2008 to 31 December 2011 and five new studies were identified. Information on process or partnership evaluations has been included where available. Meta‐analysis was performed using studies with comparable outcomes. Summary of findings table was added. The evidence base remains weak and results are largely unchanged.