BACKGROUND There is little published guidance as to the sample size required for a pilot or feasibility trial despite the fact that a sample size justification is a key element in the design of a trial. A sample size justification should give the minimum number of participants needed in order to meet the objectives of the trial. This paper seeks to describe the target sample sizes set for pilot...

In the post-genome era, disease gene mapping using dense genetic markers has become an important tool for dissecting complex inheritable diseases. Locating disease susceptibility genes using DNA-pooling experiments is a potentially economical alternative to those involving individual genotyping. The foundation of a successful DNA-pooling association test is a precise and accurate estimation of ...

We have evaluated the pitfalls in reporting sample size calculation in randomized controlled trials (RCTs) published in the 10 highest impact factor anaesthesia journals.Superiority RCTs published in 2013 were identified and checked for the basic components required for sample size calculation and replication. The difference between the reported and replicated sample size was estimated. The sou...

Adaptive study designs Animal studies Sample size calculatioin Pilot projects Animal experiments are a core element of basic medical research. Their accurate planning regarding sample size, however, poses a challenge from a biometrical point of view, since valid information is rarely given. One proposed concept includes the integration of pilot projects in animal research to encounter this shor...

OBJECTIVE To assess risk of bias and to investigate methodological issues concerning the design, conduct and analysis of randomised controlled trials (RCTs) testing acupuncture for knee osteoarthritis (KOA). METHODS PubMed, EMBASE, Cochrane Central Register of Controlled Trials and four major Chinese databases were searched for RCTs that investigated the effect of acupuncture for KOA. The Coc...

The Quality-Adjusted Time Without Symptoms or Toxicity (Q-TWiST) statistic previously introduced by Glasziou, Simes and Gelber (1990, Statistics in Medicine 9, 1259-1276) combines toxicity, disease-free survival, and overall survival information in assessing the impact of treatments on the lives of patients. This methodology has received positive reviews from clinicians as intuitive and useful,...

Recently, Wu et al. [4] have proposed the sequence kernel machine test (SKAT) to test association between genetic variants in a gene or region and a continuous or binary trait. SKAT, which uses the kernel machine regression framework, is very flexible and computationally efficient. From extensive simulation studies and real data application, it has been shown that SKAT is more powerful than the...

BACKGROUND In the evaluation of childhood obesity interventions, few researchers undertake a rigorous feasibility stage in which the design and procedures of the evaluation process are examined. Consequently, phase III studies often demonstrate methodological weaknesses. PURPOSE Our aim was to conduct a feasibility trial of the evaluation of WATCH IT, a community obesity intervention for chil...

At the design stage of a clinical trial, several assumptions have to be made. These usually include guesses about parameters that are not of direct interest but must be accounted for in the analysis of the treatment effect and also in the sample size calculation (nuisance parameters, e.g. the standard deviation or the control group event rate). We conducted a systematic review to investigate th...

OBJECTIVE To determine whether poor reporting of methods in randomised controlled trials reflects on poor methods. DESIGN Observational study. SETTING Reports of randomised controlled trials conducted by the Radiation Therapy Oncology Group since its establishment in 1968. PARTICIPANTS The Radiation Therapy Oncology Group. Outcome measures Content of reports compared with the design featu...