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Morrison et al. examine the effect on questionnaire response of
feeding back research findings to participants. As authors of the
systematic review  cited in their paper we would like to point out that
we had in fact identified eight such randomized trials.[3-10] The broad
strategy under which these trials had been classified in our review was
‘non monetary incentives’.
We are curren...
We are currently updating our systematic
review and have recently extended the search of databases to the beginning
of 2003 and have contacted the authors of potentially eligible trials. A
further two trials [11,12] have been identified and the total of 10 trials
have also been classified under the new strategy called ‘offer of research
findings’. These trials include a total of 13,642 participants. When the
results of these trials are pooled in a random effects meta analysis the
odds ratio for response with research findings is 0.92 (95% CI 0.75 to
1.11). Despite omitting to refer to these previous trials, Morrison et al.
were justified in conducting their trial: few of such trials have been
health-related and none has examined the effect this an intervention when
participants were resurveyed. However, even with the inclusion of their
new trial in our systematic review, uncertainty about the effect of
dissemination of research findings on questionnaire response remains.
The update to our systematic review now includes a total of 372
trials of methods to influence response to postal questionnaires,
classified under 98 strategies. Although many conclusions remain
unchanged our updated review presents the definitive account of the
evidence for which strategies may be used to improve response to postal
questionnaires. The updated review will appear in the Cochrane Library
later this year.
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