The case{crossover study design in principle allows testing for an acute health e ect of an exposure such as air pollution with restriction in time to remove seasonal confounding. We argue that much thinking about this design has been based on false analogies with matched case{control studies, and show that the usual design and analysis of case{crossover studies introduce a previously unrecogni...

The original analysis of genetic algorithms presents combination to be the primary mechanism of crossover. Although good solutions can be found by combination, they are often not locally optimal. Thus, a popular technique is to locally optimize each crossover solution before adding it to the population. In these \hybrid" operators, crossover can be viewed as a means of restarting the local opti...

In clinical trials, crossover design is widely used to assess treatment effects of drugs. Due to many practical issues, each patient in the study may receive only a subset of treatments under comparison, which is called an incomplete block crossover design. Correspondingly, the associated challenges are limited information and small sample size. In this article, we propose a Bayesian approach t...

abstract background: menthol is the most important active material in mint and different mechanisms have been suggested for the way mint functions, most of which emphasize its analgesic effect owing to the presence of a group of temporary protein receptors. this study investigates the efficacy of peppermint capsule in the treatment of primary dysmenorrhea, in comparison with mefenamic acid and ...

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...

OBJECTIVE To evaluate the characteristics of the design, analysis, and reporting of crossover trials for inclusion in a meta-analysis of treatment for primary open-angle glaucoma and to provide empirical evidence to inform the development of tools to assess the validity of the results from crossover trials and reporting guidelines. METHODS We searched MEDLINE, EMBASE, and Cochrane's CENTRAL r...

In cohort and case-control studies, confounding that arises as a result of differences in the distribution of determinants of the outcome between exposure groups leading to non-exchangeability are addressed by restriction, matching or with statistical models. In case-only studies, this issue is addressed by comparing each individual with his/herself. Although case-only designs use self-matching...

BACKGROUND The case-crossover design is an attractive alternative to the classical case-control design which can be used to study the onset of acute events if the risk factors of interest vary in time. By comparing exposures within cases at different time periods, the case-crossover design does not rely on control subjects which can be difficult to acquire. However, using the standard method of...