BACKGROUND The widespread incorporation of behavioral support interventions into exercise trials has sometimes caused confusion concerning the primary purpose of a trial. The purpose of the present paper is to offer some conceptual and methodological distinctions among three types of exercise trials with a view towards improving their design, conduct, reporting, and interpretation. DISCUSSION...

OBJECTIVE Although crossover trials enjoy wide use, standards for analysis and reporting have not been established. We reviewed methodological aspects and quality of reporting in a representative sample of published crossover trials. METHODS We searched MEDLINE for December 2000 and identified all randomized crossover trials. We abstracted data independently, in duplicate, on 14 design criter...

BACKGROUND Poor recruitment and retention of participants in randomised controlled trials (RCTs) is problematic but common. Clear and detailed reporting of participant flow is essential to assess the generalisability and comparability of RCTs. Despite improved reporting since the implementation of the CONSORT statement, important problems remain. This paper aims: (i) to update and extend previo...

Reference limits are estimators for 'extreme' percentiles of the distribution of a quantitative diagnostic marker in the healthy population. In most cases, interest will be in the 90% or 95% reference intervals. The standard parametric method of determining reference limits consists of computing quantities of the form X̅±c·S. The proportion of covered values in the underlying population coincide...

We propose a systematic method for testing and identifying a subgroup with an enhanced treatment effect. We adopts a change-plane technique to first test the existence of a subgroup, and then identify the subgroup if the null hypothesis on non-existence of such a subgroup is rejected. A semiparametric model is considered for the response with an unspecified baseline function and an interaction ...

The main purpose in many randomized trials is to make an inference about the average causal effect of a treatment. Therefore, on a binary outcome, the null hypothesis for the hypothesis test should be that the causal risks are equal in the two groups. This null hypothesis is referred to as the weak causal null hypothesis. Nevertheless, at present, hypothesis tests applied in actual randomized t...

Determining sample sizes for microarray experiments is important but the complexity of these experiments, and the large amounts of data they produce, can make the sample size issue seem daunting, and tempt researchers to use rules of thumb in place of formal calculations based on the goals of the experiment. Here we present formulae for determining sample sizes to achieve a variety of experimen...

OBJECTIVE To investigate the effects of social-skills training and parental training programme for children with attention deficit hyperactivity disorder (ADHD). METHODS We conducted a randomized two-armed, parallel group, assessor-blinded superiority trial consisting of social-skills training plus parental training and standard treatment versus standard treatment alone. A sample size calcula...

OBJECTIVES This study aims to assess the completeness of reporting of randomised controlled trials (RCTs) of acupuncture in the Korean literature. DESIGN Systematic review. METHODS We searched 12 Korean databases and 7 Korean journals to identify eligible RCTs of acupuncture published from 1996 to July 2011. We used the Consolidated Standards of Reporting Trials (CONSORT) checklist for para...

Justification for the original sample size calculation is made in the trial protocol. In this additional file, we provide details of the assumptions and calculations in estimating the likely width of the 95% confidence interval (CI) for the estimators, the risk difference and the log odds ratio, for the primary practitioner outcome, x-ray referral. Table 1 contains the likely widths of the 95% ...