Search Results - "Lloyd, Chris J."

A new method of identifying target groups for pronatalist policy applied to Australia by Chen, Mengni, Lloyd, Chris J, Yip, Paul S F

“…A country's total fertility rate (TFR) depends on many factors. Attributing changes in TFR to changes of policy is difficult, as they could easily be…”
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Exact confidence limits after a group sequential single arm binary trial by Lloyd, Chris J.

“…Group sequential single arm designs are common in phase II trials as well as attribute testing and acceptance sampling. After the trial is completed,…”
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Exact samples sizes for clinical trials subject to size and power constraints by Lloyd, Chris J.

“…Summary This paper first describes the difficulties in providing the required sample sizes for clinical trials that guarantee type 1 and type 2 error control…”
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Unconditional efficient one-sided confidence limits for the odds ratio based on conditional likelihood by Lloyd, Chris J., Moldovan, Max V.

“…We compare various one‐sided confidence limits for the odds ratio in a 2 × 2 table. The first group of limits relies on first‐order asymptotic approximations…”
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A comprehensive open-source library for exact required sample size in binary clinical trials by Lloyd, Chris J., Ripamonti, Enrico

“…We describe how we are creating a new and comprehensive R library solving the problem of exact sample size determination of RCTs. A crucial prerequisite for…”
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Tests for noninferiority trials with binomial endpoints: A guide to modern and quasi‐exact methods for biomedical researchers by Ripamonti, Enrico, Lloyd, Chris J.

“…Applied statisticians and pharmaceutical researchers are frequently involved in the design and analysis of clinical trials where at least one of the outcomes…”
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Accurate confidence limits for stratified clinical trials by Lloyd, Chris J.

“…For stratified 2 × 2 tables, standard approximate confidence limits can perform poorly from a strict frequentist perspective, even for moderate‐sized samples,…”
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The size accuracy of combination tests by Lloyd, Chris J.

“…Summary Adaptive clinical trials typically involve several independent stages. The P‐values from each stage are synthesized through a so‐called combination…”
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An exhaustive numerical assessment of alternative unconditional tests of a binary treatment effect by Lloyd, Chris J., Ripamonti, Enrico

“…For testing the effectiveness of a treatment on a binary outcome, a bewildering range of methods have been proposed. How similar are all these tests? What are…”
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Accurate p‐values for adaptive designs with binary endpoints by Heritier, Stephane, Lloyd, Chris J., Lô, Serigne N.

“…Adaptive designs encompass all trials allowing various types of design modifications over the course of the trial. A key requirement for confirmatory adaptive…”
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Computing exact one-sided confidence limits for treatment effect in clinical trials by Lloyd, Chris J.

“…One standard summary of a clinical trial is a confidence limit for the effect of the treatment. Unfortunately, standard approximate limits may have poor…”
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New Exact and More Powerful Unconditional Test of No Treatment Effect from Binary Matched Pairs by Lloyd, Chris J.

“…We consider the problem of testing for a difference in the probability of success from matched binary pairs. Starting with three standard inexact tests, the…”
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A scenario analysis of future Hong Kong age and labour force profiles and its implications by Lloyd, Chris J., Kwok, Raymond, Yip, Paul S. F.

“…The consequences of reduced fertility and mortality on the age distribution are an issue for most developed countries, but especially for the ‘Asian tiger’…”
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On the Exact Size of Tests of Treatment Effects in Multi-Arm Clinical Trials by Lloyd, Chris J.

“…Summary When testing treatment effects in multi‐arm clinical trials, the Bonferroni method or the method of Simes 1986) is used to adjust for the multiple…”
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Computing highly accurate or exact P-values using importance sampling by Lloyd, Chris J.

“…Especially for discrete data, standard first order P-values can suffer from poor accuracy, even for quite large sample sizes. Moreover, different test…”
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Growing rich without growing old: the impact of internal migration in China by Chen, Mengni, Lloyd, Chris J., Yip, Paul S. F.

“…In China in 2017, the elderly dependency ratio (EDR) - which is the number of elderly per 100 working-age population - was 14.8. This represents a huge…”
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Bootstrap and Second-Order Tests of Risk Difference by Lloyd, Chris J.

“…Clinical trials data often come in the form of low-dimensional tables of small counts. Standard approximate tests such as score and likelihood ratio tests are…”
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Computing highly accurate confidence limits from discrete data using importance sampling by Lloyd, Chris J., Li, Degui

“…For discrete data, frequentist confidence limits based on a normal approximation to standard likelihood based pivotal quantities can perform poorly, even for…”
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EXACT P-VALUES FOR DISCRETE MODELS OBTAINED BY ESTIMATION AND MAXIMIZATION by Lloyd, Chris J.

“…Summary In constructing exact tests from discrete data, one must deal with the possible dependence of the P‐value on nuisance parameter(s) ψ as well as the…”
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Computing highly accurate or exact -values using importance sampling by Lloyd, Chris J.

“…Especially for discrete data, standard first order P -values can suffer from poor accuracy, even for quite large sample sizes. Moreover, different test…”
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