Trial registration - why it is important

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The opening paragraph of an article in The Economist (The sounds of silence.  Sep 9th 2004) sums up the problem of not registering trials:

"SOMETIMES, no news is news. In clinical trials, where new medical treatments are tried out on human subjects, no news—an inconclusive result, indicating that the treatment is useless, or a negative one, indicating that it is harmful—can be as scientifically important as a positive result. Unfortunately, such a result is much less likely to be reported."

Not reporting the results of randomised controlled trials is increasingly seen as scientific and ethical misconduct, and the pressure to register trials to reduce biased under-reporting is growing.  Legislation in some countries now requires registration of trials, while some funding agencies and official bodies recommend it.   By registering a trial you will:
    •      Bring your trials to a wider audience
    •      Support the drive for greater openness
    •      Lead the way, before legislation demands it
    •      Add to the body of knowledge available to patients, researchers, funders, and policy makers.

One way of registering a trial is to use the International Standard Randomised Controlled Trial Number (ISRCTN) scheme.   The following text is taken from the ISRCTN website, with which the Practihc collaboration has no connection.

The International Standard Randomised Controlled Trial Number (ISRCTN)
The International Standard Randomised Controlled Trial Number (ISRCTN) scheme ( was conceived by a working group to address the difficulty of differentiating between trials. Confusion arises because different trials may have the same title, different titles may be applied to the same trial, and the titles of publications may frequently bear little resemblance to the original trial title. The solution offered is the creation of a unique numbering system for all RCTs, to simplify identification and provide a means of unambiguously tracking a trial throughout its life cycle – the ISRCTN. Records of trials to which ISRCTNs have been assigned are available in the ISRCTN Register.

Without these tools, clinicians, researchers, patients and the public will remain in ignorance about ongoing and unpublished trials or confused about which trial is which. Opportunities for collaboration and reducing duplication of research effort will be missed. Publication bias and undeclared over-reporting will lead to misleading conclusions being drawn about the forms of care most likely to benefit patients. Patients may even be subjected to trials seeking evidence that is already available.

There is a charge for registration but it is modest (for 2005 it was US$190/€150/£100 per trial).  Fees may also be waived for trials that are sponsored, funded and done in developing and transitional countries.  More details of registration are given at

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Things to consider when writing a protocol

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This page was last updated 18th April 2005.