Optimal adaptive sequential designs for crossover bioequivalence studies

In prior works, this group demonstrated the feasibility of valid adaptive sequential designs for crossover bioequivalence studies. In this paper, we extend the prior work to optimize adaptive sequential designs over a range of geometric mean test/reference ratios (GMRs) of 70–143% within each of two ranges of intra‐subject coefficient of variation (10–30% and 30–55%). These designs also introduce a futility decision for stopping the study after the first stage if there is sufficiently low likelihood of meeting bioequivalence criteria if the second stage were completed, as well as an upper limit on total study size. The optimized designs exhibited substantially improved performance characteristics over our previous adaptive sequential designs. Even though the optimized designs avoided undue inflation of type I error and maintained power at 80%, their average sample sizes were similar to or less than those of conventional single stage designs. Copyright © 2015 John Wiley & Sons, Ltd.     

Additional results for 'Sequential design approaches for bioequivalence studies with crossover designs'

In 2008, this group published a paper on approaches for two‐stage crossover bioequivalence (BE) studies that allowed for the reestimation of the second‐stage sample size based on the variance estimated from the first‐stage results. The sequential methods considered used an assumed GMR of 0.95 as part of the method for determining power and sample size. This note adds results for an assumed GMR = 0.90. Two of the methods recommended for GMR = 0.95 in the earlier paper have some unacceptable increases in Type I error rate when the GMR is changed to 0.90. If a sponsor wants to assume 0.90 for the GMR, Method D is recommended. Copyright © 2011 John Wiley & Sons, Ltd.     

The interacting effects of religion and birthplace on the labour market outcomes of Asian immigrants in Australia

Journal of Population Research - Immigration from a diverse range of source countries has been instrumental in increasing the diversity of religions among Australia’s population....     

Which women stop at one child in Australia?

The decline in fertility in Australia in the 1990s reflected both decreased first-order birth rates and decreased second-order birth rates (Kippen 2004). Whilst childlessness has been studied extensively, little attention has been paid to the progression from one to two children. This study analyses which women stop at one child using data from 1,809 parous 40–54 year olds from Wave 1 of the Household Income and Labour Dynamics in Australia (HILDA) survey. Important early lifecourse predictors of whether a woman stops her childbearing at one child are shown to be a woman s country of birth, highest level and type of schooling, and her father s occupation. A woman s marital status and her age at the time of the first birth are also shown to be significant predictors of her likelihood of not progressing to a second birth. The causes of trends over time are discussed.