The need for hand searching will diminish over the years as searching of older journals is completed. Also, journal editors are adopting the CONSORT guidelines (Consolidated Standards of Reporting Trials13), which aim to improve the standard of reporting of trials in publications. This will make it much easier to find trials electronically with simple search terms.
Other sources also need to be examined for valuable information about trials that have been performed. These are known by the term "grey literature" and include PhD and MD theses, pharmaceutical company records, conference proceedings etc. As it is known that trials with statistically significant results tend to be published more rapidly than those with less clear results,14 it follows that a systematic reviewer needs to examine unpublished data that may contain valuable negative information about an intervention.
In the past it has been difficult to find out what research is already being done. There are now web-based clinical trial registers where trials can be registered, which should make it much easier in the future and help to prevent duplication of effort. The Current Controlled Trials Meta-Register15 is an international searchable database of more than 125 000 ongoing RCTs and the National Research Register16 is a register of research within the UK NHS. Within the CSG we have an Ongoing Trials web page17 in which we invite dermatology trialists to lodge the (minimal) details of their clinical trial with their proposed outcome measures. This then provides a source of trial information for a systematic reviewer to refer to if the trial relates to their review topic. It also means that when the trial report is published the author will have proof that they have adhered to their original plans, particularly in relation to outcome measures.
The Specialised Skin Register is currently a database of reports of trials. However, many trials are carried out over several years and are multicentre studies, which often results in many publications relating to the same clinical trial. We therefore aim to gather these reports together to make the Register study based rather than report based. That should help the reviewer.
There is a unique obligation on Cochrane reviewers that they revisit their review periodically to update it in the light of new and newly unearthed evidence. This means that new reports of trials found by hand searching will be assessed. The Cochrane Collaboration is an international organisation but currently it is far too dominated by English-language publications, which may introduce their own bias.18 As more studies are found in languages other than English and are incorporated into systematic reviews, we will all gain by having a more balanced and informed view about the usefulness of interventions.
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