Investigative clinical-epidemiological or experimental studies have the objectives of describing phenomena or comparing the behavior of variables in subgroups of a population. To accomplish those objectives, the population universe is not studied in its entirety, usually because it is not accessible or viable, but mainly because it is not necessary, when a representative sample is available for...

A decision theoretic framework for sample size determination for a clinical trial is presented in which the nal decision whether to use the new treatment is taken by potential users and their medical advisers on the basis of the strength of the evidence provided by the trial. This is more realistic than the usual decision theoretic assumption that both the sample size and terminal decisions are...

BACKGROUND Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statis...

R package mixAK originally implemented routines primarily for Bayesian estimation of finite normal mixture models for possibly interval-censored data. The functionality of the package was considerably enhanced by implementing methods for Bayesian estimation of mixtures of multivariate generalized linear mixed models proposed in Komárek and Komárková (2013). Among other things, this allows for a...

In their paper [1], Drs. Mehta and Pocock illustrate the use of a particular approach to revising the maximal sample size of a randomized clinical trial (RCT) by using an interim estimate of the treatment effect. Slightly extending the results of Gao, Ware, and Mehta [2], the authors define conditions on an adaptive rule such that one can know that the naive statistical hypothesis test that ign...

Adaptive clinical trials are an innovative trial design aimed at reducing resources, decreasing time to completion and number of patients exposed to inferior interventions, and improving the likelihood of detecting treatment effects. The last decade has seen an increasing use of adaptive designs, particularly in drug development. They frequently differ importantly from conventional clinical tri...

Objective. The aim of this review is to provide the available evidence on the external use of propolis (EUP) for oral, skin, and genital diseases. Method. We searched twelve electronic databases for relevant studies up to June 2016. Randomized clinical trials (RCTs) were included and analysed. Results. Of the 286 articles identified, twelve potentially relevant studies met our inclusion criteri...

BACKGROUND Developing valid and reliable patient-reported outcome measures (PROMs) is a critical step in promoting patient-centered health care, a national priority in the U.S. Small populations or rare diseases often pose difficulties in developing PROMs using traditional methods due to small samples. METHODS To overcome the small sample size challenge while maintaining psychometric soundnes...