The editorial group responsible for this previously published document have withdrawn it from publication.
Reason for withdrawal from publication
This review is being withdrawn. A new review team have registered this title and will be writing a new review which reflects current methods and up to date evidence.
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|9 July 2014||Amended||This review is being withdrawn. A new review team have registered this title and will be writing a new review which reflects current methods and up to date evidence.|
Protocol first published: Issue 3, 1998
Review first published: Issue 4, 1998
|7 August 2008||Amended||Converted to new review format.|
|4 September 2001||New search has been performed||New search. First update September 2001 identified nine additional citations to nine studies; of these six were excluded from the review and three require further information from the authors.|
|24 November 1998||New citation required and conclusions have changed||Substantive amendment|
Sources of support
Department of Health Studies, University of York, UK.
NHS Centre for Reviews and Dissemination, University of York, UK.
Department of Health and Personal Social Services, Northern Ireland, UK.
NHS Health Technology Assessment Programme, UK.