The randomized clinical trial is the preferred research design for evaluating competing diagnostic and therapeutic alternatives, but confidence in the conclusions from a randomized clinical trial depends on the authors' attention to acknowledged methodologic and statistical standards. This survey assessed the level of attention to the problem of multiple comparisons in the analyses of contempor...

BACKGROUND: Evidence-based medicine demands the use of information from clinical trials to direct medical care. Knowledge of the principles of trial design and conduct is important to assess the validity of results. METHODS: The authors review the key principles behind clinical study design and conduct, and they summarize important biases and confounding issues. RESULTS: Clear hypotheses, a wel...

Evidence-based medicine is a redundant term to the extent that doctors have always claimed they practiced medicine on the basis of evidence. They have, however, disagreed about what exactly constitutes legitimate evidence and how to synthesize the totality of evidence in a way that supports clinical action. Despite claims to the contrary, little progress has been made in solving this hard probl...

The National Institute for Health Research (NIHR) has identified a gap in the number of people it funds who are on a pathway to become future leaders of clinical trials, compared to how much the NIHR invests in clinical trials. In order to support the clinical trials of tomorrow, it is vital that the right people are supported now to lead these trials. To address this issue, NIHR organised a wo...

Recent controversies in medical research and the increasing reliance on randomized clinical trials to inform evidence-based practice have prompted coordinated attempts to standardize reporting and register information about trials for consistency and transparency. The Consolidated Standards of Reporting Trials guidelines (D. G. Altman et al., 2001) and trial registry are described in this artic...

Background Careful site selection methods and tools such as questionnaires have evolved to become “best” practice in the commercial and non-commercial clinical trials setting. However, there is little evidence in the literature of the value of such methodology on trial delivery and there is no generally acceptable model or tool available for use in site selection. The Nottingham Clinical Trials...

Clinical trial registries are being increasingly acknowledged worldwide. We searched for possibly trustworthy online registries that are not already included in the International Clinical Trials Registry Platform to evaluate whether other useful trial data sources exist and whether they could potentially be consulted, since the strategy search within this platform has recently been questioned. ...

Conventional phase 2 clinical trials are typically single-arm experiments, with outcome characterized by one binary "response" variable. Clinical investigators are poorly served by such conventional methodology. We contend that phase 2 trials are inherently comparative, with the results of the comparison determining whether to conduct a subsequent phase 3 trial. When different treatments are st...

Controversy exists regarding the ethics of using placebo control groups in clinical trials when effective treatments exist. The debate was fuelled by the announcement of the fifth revision of the Declaration of Helsinki in 2000. This study reviews the history and scientific background surrounding the controversy and investigates the prevailing attitudes of Hong Kong researchers regarding this i...