Crossover Designs

This monograph presents a comprehensive and up-to-date account of the developments in optimality aspects of crossover designs. Crossover designs are immensely useful in various areas of human investigation including agriculture, animal nutrition, clinical trials, pharmaceutical studies, biological assays, weather modification experiments, sensory evaluation of food products and learning experiments. Research on the optimality aspects of crossover designs has developed only in the last three decades, and it has now emerged as a potential field for further investigation. This book is the first comprehensive treatise on this subject. It covers optimal crossover designs at length by consolidating vast amounts of material from the literature, and includes many recent and deep results. It is expected that this book will not only provide a one-stop reference for the available results, but also encourage further research in this area of substantial practical relevance.

A comprehensive and practical resource for analyses of crossover designs For ethical reasons, it is vital to keep the number of patients in a clinical trial as low as possible. As evidenced by extensive research publications, crossover design can be a useful and powerful tool to reduce the number of patients needed for a parallel group design in studying treatments for non-curable chronic diseases. This book introduces commonly-used and well-established statistical tests and estimators in epidemiology that can easily be applied to hypothesis testing and estimation of the relative treatment effect for various types of data scale in crossover designs. Models with distribution-free random effects are assumed and hence most approaches considered here are semi-parametric. The book provides clinicians and biostatisticians with the exact test procedures and exact interval estimators, which are applicable even when the number of patients in a crossover trial is small. Systematic discussion on sample size determination is also included, which will be a valuable resource for researchers involved in crossover trial design. Key features: Provides exact test procedures and interval estimators, which are especially of use in small-sample cases. Presents most test procedures and interval estimators in closed-forms, enabling readers to calculate them by use of a pocket calculator or commonly-used statistical packages. Each chapter is self-contained, allowing the book to be used a reference resource. Uses real-life examples to illustrate the practical use of test procedures and estimators Provides extensive exercises to help readers appreciate the underlying theory, learn other relevant test procedures and understand how to calculate the required sample size. Crossover Designs: Testing, Estimation and Sample Size will be a useful resource for researchers from biostatistics, as well as pharmaceutical and clinical sciences. It can also be used as a textbook or reference for graduate students studying clinical experiments.

A comprehensive and practical resource for analyses of crossover designs For ethical reasons, it is vital to keep the number of patients in a clinical trial as low as possible. As evidenced by extensive research publications, crossover design can be a useful and powerful tool to reduce the number of patients needed for a parallel group design in studying treatments for non-curable chronic diseases. This book introduces commonly-used and well-established statistical tests and estimators in epidemiology that can easily be applied to hypothesis testing and estimation of the relative treatment effect for various types of data scale in crossover designs. Models with distribution-free random effects are assumed and hence most approaches considered here are semi-parametric. The book provides clinicians and biostatisticians with the exact test procedures and exact interval estimators, which are applicable even when the number of patients in a crossover trial is small. Systematic discussion on sample size determination is also included, which will be a valuable resource for researchers involved in crossover trial design. Key features: Provides exact test procedures and interval estimators, which are especially of use in small-sample cases. Presents most test procedures and interval estimators in closed-forms, enabling readers to calculate them by use of a pocket calculator or commonly-used statistical packages. Each chapter is self-contained, allowing the book to be used a reference resource. Uses real-life examples to illustrate the practical use of test procedures and estimators Provides extensive exercises to help readers appreciate the underlying theory, learn other relevant test procedures and understand how to calculate the required sample size. Crossover Designs: Testing, Estimation and Sample Size will be a useful resource for researchers from biostatistics, as well as pharmaceutical and clinical sciences. It can also be used as a textbook or reference for graduate students studying clinical experiments.

The Design of Active Crossovers is a unique guide to the design of high-quality circuitry for splitting audio frequencies into separate bands and directing them to different loudspeaker drive units specifically designed for handling their own range of frequencies. Traditionally this has been done by using passive crossover units built into the loudspeaker boxes; this is the simplest solution, but it is also a bundle of compromises. The high cost of passive crossover components, and the power losses in them, means that passive crossovers have to use relatively few parts. This limits how well the crossover can do its basic job. Active crossovers, sometimes called electronic crossovers, tackle the problem in a much more sophisticated manner. The division of the audio into bands is performed at low signal levels, before the power amplifiers, where it can be done with much greater precision. Very sophisticated filtering and response-shaping networks can be built at comparatively low cost. Time-delay networks that compensate for phyical misalignments in speaker construction can be implemented easily; the equivalent in a passive crossover is impractical because of the large cost and the heavy signal losses. Active crossover technology is also directly applicable to other band-splitting signal-processing devices such as multi-band compressors. The use of active crossovers is increasing. They are used by almost every sound reinforcement system, by almost every recording studio monitoring set-up, and to a small but growing extent in domestic hifi. There is a growing acceptance in the hifi industry that multi-amplification using active crossovers is the obvious next step (and possibly the last big one) to getting the best possible sound. There is also a large usage of active crossovers in car audio, with the emphasis on routing the bass to enormous low-frequency loudspeakers. One of the very few drawbacks to using the active crossover approach is that it requires more power amplifiers; these have often been built into the loudspeaker, along with the crossover, and this deprives the customer of the chance to choose their own amplifier, leading to resistance to the whole active crossover philosophy. A comprehensive proposal for solving this problem is an important part of this book. The design of active crossovers is closely linked with that of the loudspeakers they drive. A chapter gives a concise but complete account of all the loudspeaker design issues that affect the associated active crossover. This book is packed full of valuable information, with virtually every page revealing nuggets of specialized knowledge never before published. Essential points of theory bearing on practical performance are lucidly and thoroughly explained, with the mathematics kept to an essential minimum. Douglas' background in design for manufacture ensures he keeps a wary eye on the cost of things. Features: Crossover basics and requirements The many different crossover types and how they work Design almost any kind of active filter with minimal mathematics Make crossover filters with very low noise and distortion Make high-performance time-delay filters that give a constant delay over a wide range of frequency Make a wide variety of audio equaliser stages: shelving, peaking and notch characteristics All about active crossover system design for optimal noise and dynamic range There is a large amount of new material that has never been published before. A few examples: using capacitance multipliers in biquad equalisers, opamp output biasing to reduce distortion, the design of NTMTM notch crossovers, the design of special filters for filler-driver crossovers, the use of mixed capacitors to reduce filter distortion, differentially elevated internal levels to reduce noise, and so on. Douglas wears his learning lightly, and this book features the engaging prose style familiar from his other books The Audio Power Amplifier Design Handbook, Self on Audio, and the recent Small Signal Audio Design.

Comprehensive book that suggests ways to improve the efficiency of clinical trials and the development of interventions in the neurosciences.

This unique textbook integrates statistical concepts into evidence-based clinical practice and patient management. Research concepts and techniques are drawn from epidemiology, bio-statistics, and psychometrics, as well as educational and social science research. Clinical examples throughout the text illustrate practical and scientifically sound applications of the concepts. Data tables and research vignettes highlight statistical distributions involving probability. Methods to locate and utilize web-based information relevant to clinical research are discussed, and web URLs are provided. Further learning is encouraged by the inclusion of suggested activities, recommended readings, references, and a comprehensive glossary of research terms. Additional resources are available at a Connection Website, connection.LWW.com/go/stommel.

Methods and Applications of Statistics in Clinical Trials, Volume 2: Planning, Analysis, and Inferential Methods includes updates of established literature from the Wiley Encyclopedia of Clinical Trials as well as original material based on the latest developments in clinical trials. Prepared by a leading expert, the second volume includes numerous contributions from current prominent experts in the field of medical research. In addition, the volume features: • Multiple new articles exploring emerging topics, such as evaluation methods with threshold, empirical likelihood methods, nonparametric ROC analysis, over- and under-dispersed models, and multi-armed bandit problems • Up-to-date research on the Cox proportional hazard model, frailty models, trial reports, intrarater reliability, conditional power, and the kappa index • Key qualitative issues including cost-effectiveness analysis, publication bias, and regulatory issues, which are crucial to the planning and data management of clinical trials

Cross-over trials are an important class of design used in the pharmaceutical industry and medical research, and their use continues to grow. Cross-over Trials in Clinical Research, Second Edition has been fully updated to include the latest methodology used in the design and analysis of cross-over trials. It includes more background material, greater coverage of important statistical techniques, including Bayesian methods, and discussion of analysis using a number of statistical software packages. * Comprehensive coverage of the design and analysis of cross-over trials. * Each technique is carefully explained and the mathematics is kept to a minimum. * Features many real and original examples, taken from the author's vast experience. * Includes discussion of analysis using SAS, S-Plus and, GenStat, StatXact and Excel. * Written in a style suitable for statisticians and physicians alike. * Computer programs to accompany the examples in the book can be downloaded from the Web Primarily aimed at statisticians and researchers working in the pharmaceutical industry, the book will also appeal to physicians involved in clinical research and students of medical statistics.