| Date | Event | Description |
|---|---|---|
| 1 May 2009 | New citation required and major changes | This protocol has been substantially updated since first publication in 2001 and has been co‐registered within the Campbell Collaboration. |
| 9 September 2008 | Amended | Hannah Jones added to authorline |
| 9 September 2008 | Amended | Converted to new review format. |
| 4 July 2007 | Amended | Camilla Thorgaard added to authorline; Sima Pindoria and Carol Joughin removed |
| 20 April 2005 | New citation required and conclusions have changed | Substantive amendment |
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