"Most definitions of SRs suggest you require all trials. Therefore
not looking for unpublished studies seems to invalidate them from being SRs."
I reviewed some definitions discussed on HIFA recently and indeed
some of them can be interpreted to imply that you require 'all
trials' (or, more accurately, all relevant studies), including
unpublished studies. But this is clearly an impossible ideal - my
interpretation of these definitions, in the real world, is clearly
that they refer to all *available* evidence. The non-availability of
some of the evidence limits, more or less, the value of the
synthesis, but does not invalidate such synthesis. As Vlassov has
said: "the SRs have the weaknesses, as well as other human
instruments, but they are still the best instrument for the purpose"
Best wishes, Neil
Let's build a future where people are no longer dying for lack of
healthcare information - Join HIFA: www.hifa.org
HIFA profile: Neil Pakenham-Walsh is the coordinator of the HIFA
campaign (Healthcare Information For All - www.hifa.org ) and current
chair of the Dgroups Foundation (www.dgroups.info), which supports
700 communities of practice for international development, social
justice and global health. Twitter: @hifa_org FB:
facebook.com/HIFAdotORG [log in to unmask]
|