The estimation of semiparametric generalized linear models

Empirical thesis.Bibliography: pages 137-141.1. Introduction -- 2. Literature review -- 3. The semiparametric generalized linear model -- 4. The semiparametric generalized linear model with canonical link -- 5. Application to real data sets -- 6. Conclusions and future work -- Appendix -- References.In this thesis, a novel method for fitting the semiparametric generalized linear model (SPGLM) is developed and tested. We demonstrate that this provides an effective model fitting algorithm to the SP-GLM, particularly, when dealing with very large data sets. We also propose another special SP-GLM and discuss how to fit this special model. This special SP-GLM assumes the canonical link function, which simplifies the algorithm to fit this model.GLMs are widely used for data analysis. However, in some applications, GLMs do not perform well in model fitting when the selected distribution for the response data is inaccurate.The SP-GLM with a nonparametric reference density extends the conventional GLMs. The SP-GLM offers flexibility in regression modelling by relaxing the requirement of a known response distribution in GLMs to only require that the response variable has a distribution from some exponential family. However, a limitation has been observed in the application of the existing SP-GLM method (Huang, 2014) on large data sets, presumably due to the significant increase in the number of constraints for the SP-GLM for large sample sizes. The proposed new SP-GLM methods in this thesis will enable to fit SP-GLM to very large data sets.In this research, the focus is on the regression coefficients estimations and inferences. An iterative algorithm is developed for estimation of the regression coefficients and the reference density simultaneously. The asymptotic properties of the estimators subject to active constraints are also provided.Performance of the proposed methods are tested through simulation studies and real data applications. The simulation results have indicated effectiveness for the methods proposed in this research, with accurate estimation of the regression coefficients, as well as inference. The conclusion reached in this research is that the proposed model fitting methods enhance the capacity of the SP-GLM to handle very large data sets with fast convergence.Mode of access: World wide web1 online resource (xviii, 141 pages) graphs, table

Big data and its implications for the statistics profession and statistics education

Theoretical thesis.Bibliography: pages 80-82.1. Introduction -- 2. Methodology and data collection -- 3. Results -- 4. Conclusions.The convergence of computer and communications technology, the processing speed of the computers, and the widespread use of the internet around the world have led us to the age of Big Data. Massive volumes of data have been and are being collected and this far outstrips the capacity to analyse the data and convert it into useful and usable information. The need for people who can analyse the data and obtain useful and usable information from it has led to a new career path: the “data scientist”. The data scientist is a kind of hybrid of a statistician and a computer scientist / IT professional. Big Data and its analysis is an area in which industry is leading and academia seems to be playing catch up. Universities are responding to the changing needs of industry and government by introducing new degree programs and units of study. In this thesis, we investigate the perceptions of graduates working in the analysis of Big Data and the perceptions of academics about the types of expertise and the types of software skills required for working in this new field via online surveys. This facilitates comparison between the perceptions of statisticians and of computer scientists about what expertise and software skills are required, and provides information useful for the purpose of developing the curriculum for new degrees in data science and statistics which is urgently needed.Mode of access: World wide web1 online resource (vi, 82 pages

Global impacts of Covid-19 on lifestyles and health and preparation preferences: an international survey of 30 countries

Background: The health area being greatest impacted by coronavirus disease 2019 (COVID-19) and residents' perspective to better prepare for future pandemic remain unknown. We aimed to assess and make cross-country and cross-region comparisons of the global impacts of COVID-19 and preparation preferences of pandemic. Methods: We recruited adults in 30 countries covering all World Health Organization (WHO) regions from July 2020 to August 2021. 5 Likert-point scales were used to measure their perceived change in 32 aspects due to COVID-19 (-2 = substantially reduced to 2 = substantially increased) and perceived importance of 13 preparations (1 = not important to 5 = extremely important). Samples were stratified by age and gender in the corresponding countries. Multidimensional preference analysis displays disparities between 30 countries, WHO regions, economic development levels, and COVID-19 severity levels. Results: 16 512 adults participated, with 10 351 females. Among 32 aspects of impact, the most affected were having a meal at home (mean (m) = 0.84, standard error (SE) = 0.01), cooking at home (m = 0.78, SE = 0.01), social activities (m = -0.68, SE = 0.01), duration of screen time (m = 0.67, SE = 0.01), and duration of sitting (m = 0.59, SE = 0.01). Alcohol (m = -0.36, SE = 0.01) and tobacco (m = -0.38, SE = 0.01) consumption declined moderately. Among 13 preparations, respondents rated medicine delivery (m = 3.50, SE = 0.01), getting prescribed medicine in a hospital visit / follow-up in a community pharmacy (m = 3.37, SE = 0.01), and online shopping (m = 3.33, SE = 0.02) as the most important. The multidimensional preference analysis showed the European Region, Region of the Americas, Western Pacific Region and countries with a high-income level or medium to high COVID-19 severity were more adversely impacted on sitting and screen time duration and social activities, whereas other regions and countries experienced more cooking and eating at home. Countries with a high-income level or medium to high COVID-19 severity reported higher perceived mental burden and emotional distress. Except for low- and lower-middle-income countries, medicine delivery was always prioritised. Conclusions: Global increasing sitting and screen time and limiting social activities deserve as much attention as mental health. Besides, the pandemic has ushered in a notable enhancement in lifestyle of home cooking and eating, while simultaneously reducing the consumption of tobacco and alcohol. A health care system and technological infrastructure that facilitate medicine delivery, medicine prescription, and online shopping are priorities for coping with future pandemics

International survey for assessing COVID-19’s impact on fear and health: study protocol

Introduction COVID-19, caused by the SARS-CoV-2, has been one of the most highly contagious and rapidly spreading virus outbreak. The pandemic not only has catastrophic impacts on physical health and economy around the world, but also the psychological well-being of individuals, communities and society. The psychological and social impacts of the COVID-19 pandemic internationally have not been well described. There is a lack of international study assessing health-related impacts of the COVID-19 pandemic, especially on the degree to which individuals are fearful of the pandemic. Therefore, this study aims to (1) assess the health-related impact of the COVID-19 pandemic in community-dwelling individuals around the world; (2) determine the extent various communities are fearful of COVID-19 and (3) identify perceived needs of the population to prepare for potential future pandemics.Methods and analysis This global study involves 30 countries. For each country, we target at least 500 subjects aged 18 years or above. The questionnaires will be available online and in local languages. The questionnaires include assessment of the health impacts of COVID-19, perceived importance of future preparation for the pandemic, fear, lifestyles, sociodemographics, COVID-19-related knowledge, e-health literacy, out-of-control scale and the Patient Health Questionnaire-4. Descriptive statistics will be used to describe participants’ characteristics, perceptions on the health-related impacts of COVID-19, fear, anxiety and depression, lifestyles, COVID-19 knowledge, e-health literacy and other measures. Univariable and multivariable regression models will be used to assess the associations of covariates on the outcomes.Ethics and dissemination The study has been reviewed and approved by the local ethics committees in participating countries, where local ethics approval is needed. The results will be actively disseminated. This study aims to map an international perspective and comparison for future preparation in a pandemic

Key lifestyles and interim health outcomes for effective interventions in general populations: A network analysis of a large international observational study

Background The interconnected nature of lifestyles and interim health outcomes implies the presence of the central lifestyle, central interim health outcome and bridge lifestyle, which are yet to be determined. Modifying these factors holds immense potential for substantial positive changes across all aspects of health and lifestyles. We aimed to identify these factors from a pool of 18 lifestyle factors and 13 interim health outcomes while investigating potential gender and occupation differences. Methods An international cross-sectional study was conducted in 30 countries across six World Health Organization regions from July 2020 to August 2021, with 16 512 adults self-reporting changes in 18 lifestyle factors and 13 interim health outcomes since the pandemic. Results Three networks were computed and tested. The central variables decided by the expected influence centrality were consumption of fruits and vegetables (centrality = 0.98) jointly with less sugary drinks (centrality = 0.93) in the lifestyles network; and quality of life (centrality = 1.00) co-dominant (centrality = 1.00) with less emotional distress in the interim health outcomes network. The overall amount of exercise had the highest bridge expected influence centrality in the bridge network (centrality = 0.51). No significant differences were found in the network global strength or the centrality of the aforementioned key variables within each network between males and females or health workers and non-health workers (all P-values >0.05 after Holm-Bonferroni correction). Conclusions Consumption of fruits and vegetables, sugary drinks, quality of life, emotional distress, and the overall amount of exercise are key intervention components for improving overall lifestyle, overall health and overall health via lifestyle in the general population, respectively. Although modifications are needed for all aspects of lifestyle and interim health outcomes, a larger allocation of resources and more intensive interventions were recommended for these key variables to produce the most cost-effective improvements in lifestyles and health, regardless of gender or occupation