Samuel J Clark
Datos Biográficos
| ID | 3589556 |
|---|---|
| NOMBRE | Samuel J Clark |
| NOMBRES | Samuel J |
| APELLIDO | Clark |
| FIRMA | CLARK S J |
| AFILIACIONES | University of the Witwatersrand |
| ORCID | 0000-0002-4929-6231 |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 41 |
| TOTAL DE CITAS | 191 |
| TOTAL COMO AUTOR | 41 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1980 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2025 |
| ÍNDICE H | 8 |
These Guys are Weird as Hell’
Young women's travel safety and the journey to work
The relationship between women's everyday lived travel experiences as daily commuters and their employment history and potential has not been adequately researched and documented in African contexts. This multidisciplinary study, utilising an innovative action research methodology, compares experiences of young women (18-35y) resident in low-income neighbourhoods of three diverse African cities - Abuja, Cape Town and Tunis. It examines the challe…
Engaging citizens from low-income communities in transport planning
This paper draws on experience from a series of transport-focused studies built round peer research with community members resident in low-income neighbourhoods at the periphery of three major cities: Abuja, Cape Town and Tunis. These were conducted firstly with young women aged 18–35 in all three cities over a four-year period (2019–2022, i.e. spanning the pandemic), followed by a recently completed pilot with young men in the same age group (bu…
Mortality variability and differentials by age and causes of death in rural South Africa, 1994–2018
INTRODUCTION: Understanding mortality variability by age and cause is critical to identifying intervention and prevention actions to support disadvantaged populations. We assessed mortality changes in two rural South African populations over 25 years covering pre-AIDS and peak AIDS epidemic and subsequent antiretroviral therapy (ART) availability. METHODS: Using population surveillance data from the Agincourt Health and Socio-Demographic Surveill…
Understanding Household Dynamics From the Ground Up
Investigations into household structure in low- and middle-income countries (LMICs) provide important insight into how families manage domestic life in response to resource allocation and caregiving needs during periods of rapid sociopolitical and health-related challenges. Recent evidence on household structure in many LMICs contrasts with long-standing viewpoints of worldwide convergence to a Western nuclearized household model. Here, we adopt …
Agreement between cause of death assignment by computer-coded verbal autopsy methods and physician coding of verbal autopsy interviews in South Africa
BACKGROUND: The South African national cause of death validation (NCODV 2017/18) project collected a national sample of verbal autopsies (VA) with cause of death (COD) assignment by physician-coded VA (PCVA) and computer-coded VA (CCVA). OBJECTIVE: The performance of three CCVA algorithms (InterVA-5, InSilicoVA and Tariff 2.0) in assigning a COD was compared with PCVA (reference standard). METHODS: Seven performance metrics assessed individual an…
The lived experiences of women workers in Africa's transport sector
This paper draws on ethnographic research conducted 2019–2022 in three quite diverse city regions - Abuja, Cape Town and Tunis - to understand women's lived experiences of work in the road transport sector. The strength of connection between male identity and motor-mobility in Africa is ubiquitous and has rarely been questioned by transport sector actors. Women are still largely absent from the story, constrained at least partly by hegemonic norm…
Twin epidemics
Our results indicate that HIV and elevated blood pressure are acting as separate, non-interacting epidemics affecting high proportions of the older adult population. PLWH with unsuppressed viral load were at higher mortality risk compared to those uninfected. Systolic blood pressure was a mortality risk factor independent of HIV status. As antiretroviral therapy becomes more widespread, further longitudinal follow-up is needed to understand how t…
Health and demographic surveillance systems in low- and middle-income countries
Health and Demographic Surveillance Systems (HDSS) have been developed in several low- and middle-income countries (LMICs) in Africa and Asia. This paper reviews their history, state of the art and future potential and highlights substantial areas of contribution by the late Professor Peter Byass.Historically, HDSS appeared in the second half of the twentieth century, responding to a dearth of accurate population data in poorly resourced settings…
Estimating causes of death where there is no medical certification
Over the past 70 years, significant advances have been made in determining the causes of death in populations not served by official medical certification of cause at the time of death using a technique known as Verbal Autopsy (VA). VA involves an interview of the family or caregivers of the deceased after a suitable bereavement interval about the circumstances, signs and symptoms of the deceased in the period leading to death. The VA interview d…
The action dynamics of native and non-native speakers of English in processing active and passive sentences
This study investigates processing of passive and active constructions between native speakers (NS) and non-native speakers (NNS) of English using traditional on-line mechanisms such as response time in conjunction with techniques that capitalize on the parallel activation of distributed mental representations during online syntactic processing. In the current study, hand motions captured by a mouse-tracking system were used to index listeners’ c…
Clusters of HIV Risk and Protective Sexual Behaviors in Agincourt, Rural South Africa
A General Age-Specific Mortality Model With an Example Indexed by Child Mortality or Both Child and Adult Mortality
The majority of countries in Africa and nearly one-third of all countries require mortality models to infer the complete age schedules of mortality that are required to conduct population estimates, projections/forecasts, and other tasks in demography and epidemiology. Models that relate child mortality to mortality at other ages are important because almost all countries have measures of child mortality. A general, parameterizable component mode…
Sexual behavior and HIV risk across the life course in rural South Africa
There is limited information about sexual behavior among older Africans, which is problematic given high HIV rates among older adults. We use a population-based survey among people aged 15-80+ to examine the prevalence of sexual risk and protective behaviors in the context of a severe HIV epidemic. We focus on variation across the life course, gender and HIV serostatus to compare the similarities and differences of young, middle aged, and older a…
Probabilistic population projections for countries with generalized HIV/Aids epidemics
In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-t…
Progression of the epidemiological transition in a rural South African setting
This typical rural South African population is experiencing a protracted epidemiological transition. The intersection and interaction of HIV/AIDS and antiretroviral treatment, non-communicable disease risk factors and complex social and behavioral changes will impact on continued progress in reducing preventable mortality and improving health across the life course. Integrated healthcare planning and program delivery is required to improve access…
Assessing Changes in Household Socioeconomic Status in Rural South Africa, 2001-2013
Bayesian population reconstruction of female populations for less developed and more developed countries
We show that Bayesian population reconstruction, a recent method for estimating past populations by age, works for data of widely varying quality. Bayesian reconstruction simultaneously estimates age-specific population counts, fertility rates, mortality rates, and net international migration flows from fragmentary data, while formally accounting for measurement error. As inputs, Bayesian reconstruction uses initial bias-reduced estimates of stan…
Let's Talk about Sex, Maybe
Researchers are often skeptical of sexual behavior surveys: Respondents may lie or forget details of their intimate lives, and interviewers may exercise authority in how they capture responses. We use data from a 2010-2011 cross-sectional sexual behavior survey in rural South Africa to explore who says what to whom about their sexual lives. Results show an effect of fieldworker age across outcomes: Respondents report "safer," more "responsible" s…
Cardiometabolic disease risk and HIV status in rural South Africa
Sub-Saharan Africa is facing intersecting epidemics of HIV and hypertension. In this setting, around half the adult population require long-term care for at least one of HIV, hypertension or diabetes. Together with the adverse effects that HIV and its treatment have on lipids, this may have serious implications for the South African health care system. Monitoring of the interaction of HIV, ART use, and cardiometabolic disease is needed at both in…
Migration and the epidemiological transition
BACKGROUND: Migration and urbanization are central to sustainable development and health, but data on temporal trends in defined populations are scarce. Healthy men and women migrate because opportunities for employment and betterment are not equally distributed geographically. The disruption can result in unhealthy exposures and environments and income returns for the origin household. OBJECTIVES: The objectives of the paper are to describe the …
The INDEPTH standard population for low- and middle-income countries, 2013
Crude rates such as the crude death rate are functions of both the age-specific rates and the age composition of a population. However, differences in the age structure between two populations or two time periods can result in specious differences in the corresponding crude rates making direct comparisons between populations or across time inappropriate. Therefore, when comparing crude rates between populations, it is desirable to eliminate or mi…
Male and female sterility in Zambia
BACKGROUND: Population measures of sterility are traditionally constructed for women, despite fertility and sterility being conditions of the couple. Estimates of male sterility provide insight into population-level sterility, and complement estimates based solely on women. OBJECTIVE: This study seeks to estimate male sterility for the Gwembe Tonga of Zambia using male birth histories collected by the Gwembe Tonga Research Project from 1957 to 19…
Prevalence of HIV among those 15 and older in rural South Africa
A greater knowledge of the burden of HIV in rural areas of Southern Africa is needed, especially among older adults. We conducted a cross-sectional biomarker survey in the rural South African Agincourt Health and Socio-demographic Surveillance site in 2010-2011 and estimated HIV prevalence and risk factors. Using an age-sex stratified random sample of ages 15+, a total of 5037 (65.7%) of a possible 7662 individuals were located and 4362 (86.6%) c…
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Social Origins of the Irish Land War
Arguing that social movements can be explained and understood only in a comparative historical perspective and not in terms of immediate social or political conditions, the author identifies the causes of the Land War in the evolution of social structure and collective action in the Irish countryside over the course of the nineteenth century. Originally published in 1979. The Princeton Legacy Library uses the latest print-on-demand technology to …
Probabilistic Projections of the Total Fertility Rate for All Countries
We describe a Bayesian projection model to produce country-specific projections of the total fertility rate (TFR) for all countries. The model decomposes the evolution of TFR into three phases: pre-transition high fertility, the fertility transition, and post-transition low fertility. The model for the fertility decline builds on the United Nations Population Division’s current deterministic projection methodology, which assumes that fertility wi…
Assessing Changes in Household Socioeconomic Status in Rural South Africa, 2001-2013
Child Mobility, Maternal Status, and Household Composition in Rural South Africa
This article examines the influence of maternal status, socioeconomic status of the household, and household composition on the mobility of children aged 0–14 in Mpumalanga Province, South Africa, from 1999 to 2008. Using data from the Agincourt Health and Demographic Surveillance System, we found that children whose mothers were temporary migrants, living elsewhere, or dead had higher odds of moving than children whose mothers were coresident. O…
Ten Thousand Tonga
The Gwembe Study was launched in 1956 to monitor the responses of 57,000 Tonga-speakers from the Middle Zambezi Valley to involuntary relocation. Since then, periodic censuses and frequent field visits have generated a wide variety of information. This article examines the demography of four Gwembe Tonga villages from 1956 to 1991, a period characterized first by relocation, then prosperity, and finally by economic hardship. White nuptiality does…
Formations of Violence
Let's Talk about Sex, Maybe
Researchers are often skeptical of sexual behavior surveys: Respondents may lie or forget details of their intimate lives, and interviewers may exercise authority in how they capture responses. We use data from a 2010-2011 cross-sectional sexual behavior survey in rural South Africa to explore who says what to whom about their sexual lives. Results show an effect of fieldworker age across outcomes: Respondents report "safer," more "responsible" s…
Estimating trends in the total fertility rate with uncertainty using imperfect data
BACKGROUND: Estimating the total fertility rate is challenging for many developing countries because of limited data and varying data quality. A standardized, reproducible approach to produce estimates that include an uncertainty assessment is desired. METHODS: We develop a method to estimate and assess uncertainty in the total fertility rate over time, based on multiple imperfect observations from different data sources, including surveys and ce…
A General Age-Specific Mortality Model With an Example Indexed by Child Mortality or Both Child and Adult Mortality
The majority of countries in Africa and nearly one-third of all countries require mortality models to infer the complete age schedules of mortality that are required to conduct population estimates, projections/forecasts, and other tasks in demography and epidemiology. Models that relate child mortality to mortality at other ages are important because almost all countries have measures of child mortality. A general, parameterizable component mode…
The age pattern of increases in mortality affected by HIV
BACKGROUND: We investigate the sex-age-specific changes in the mortality of a prospectively monitored rural population in South Africa. We quantify changes in the age pattern of mortality in a parsimonious way by estimating the eight parameters of the Heligman-Pollard (HP) model of age-specific mortality. In its traditional form this model is difficult to fit and does not account for uncertainty. OBJECTIVE: 1. To quantify changes in the sex-age p…
Estimates of Age-Specific Reductions in HIV Prevalence in Uganda
BACKGROUND: Much of our knowledge of the epidemiology and demography of HIV epidemics in Africa is derived from models fit to sparse, non-representative data. These often average over age and other important dimensions, rarely quantify uncertainty, and typically do not impose consistency on the epidemiology and the demography of the population. OBJECTIVE: This work conducts an empirical investigation of the history of the HIV epidemic in Uganda a…
Young women's travel safety and the journey to work
The relationship between women's everyday lived travel experiences as daily commuters and their employment history and potential has not been adequately researched and documented in African contexts. This multidisciplinary study, utilising an innovative action research methodology, compares experiences of young women (18-35y) resident in low-income neighbourhoods of three diverse African cities - Abuja, Cape Town and Tunis. It examines the challe…
Probabilistic population projections for countries with generalized HIV/Aids epidemics
In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-t…
Bayesian population reconstruction of female populations for less developed and more developed countries
We show that Bayesian population reconstruction, a recent method for estimating past populations by age, works for data of widely varying quality. Bayesian reconstruction simultaneously estimates age-specific population counts, fertility rates, mortality rates, and net international migration flows from fragmentary data, while formally accounting for measurement error. As inputs, Bayesian reconstruction uses initial bias-reduced estimates of stan…
Understanding Household Dynamics From the Ground Up
Investigations into household structure in low- and middle-income countries (LMICs) provide important insight into how families manage domestic life in response to resource allocation and caregiving needs during periods of rapid sociopolitical and health-related challenges. Recent evidence on household structure in many LMICs contrasts with long-standing viewpoints of worldwide convergence to a Western nuclearized household model. Here, we adopt …
The lived experiences of women workers in Africa's transport sector
This paper draws on ethnographic research conducted 2019–2022 in three quite diverse city regions - Abuja, Cape Town and Tunis - to understand women's lived experiences of work in the road transport sector. The strength of connection between male identity and motor-mobility in Africa is ubiquitous and has rarely been questioned by transport sector actors. Women are still largely absent from the story, constrained at least partly by hegemonic norm…
Clusters of HIV Risk and Protective Sexual Behaviors in Agincourt, Rural South Africa
More on the Cohort-Component Model of Population Projection in the Context of HIV/Aids
This article presents an extension of the cohort-component model of population projection (CCMPP) first formulated by Heuveline (2003) that is capable of modeling a population affected by HIV. Heuveline proposes a maximum likelihood approach to estimate the age profile of HIV incidence that produced the HIV epidemics in East Africa during the 1990s. We extend this work by developing the Leslie matrix representation of the CCMPP, which greatly fac…
Toward a Unified Timestamp with explicit precision
Demographic and health surveillance (DS) systems monitor and document individual and group-level processes in well-defined populations over long periods of time. The resulting data are complex and inherently temporal. Established methods of storing and manipulating temporal data are unable to adequately address the challenges posed by these data. Building on existing standards, a temporal framework and notation are presented that are able to fait…
Social Origins of the Irish Land War
Arguing that social movements can be explained and understood only in a comparative historical perspective and not in terms of immediate social or political conditions, the author identifies the causes of the Land War in the evolution of social structure and collective action in the Irish countryside over the course of the nineteenth century. Originally published in 1979. The Princeton Legacy Library uses the latest print-on-demand technology to …
Formations of Violence
Ten Thousand Tonga
The Gwembe Study was launched in 1956 to monitor the responses of 57,000 Tonga-speakers from the Middle Zambezi Valley to involuntary relocation. Since then, periodic censuses and frequent field visits have generated a wide variety of information. This article examines the demography of four Gwembe Tonga villages from 1956 to 1991, a period characterized first by relocation, then prosperity, and finally by economic hardship. White nuptiality does…
Toward a Unified Timestamp with explicit precision
Demographic and health surveillance (DS) systems monitor and document individual and group-level processes in well-defined populations over long periods of time. The resulting data are complex and inherently temporal. Established methods of storing and manipulating temporal data are unable to adequately address the challenges posed by these data. Building on existing standards, a temporal framework and notation are presented that are able to fait…
A general temporal data model and the structured population event history register
At this time there are 37 demographic surveillance system sites active in sub-Saharan Africa, Asia and Central America, and this number is growing continuously. These sites and other longitudinal population and health research projects generate large quantities of complex temporal data in order to describe, explain and investigate the event histories of individuals and the populations they constitute. This article presents possible solutions to s…
Research into health, population and social transitions in rural South Africa
Rationale for study: Vital registration is generally lacking in infrastructurally weak areas where health and development problems are most pressing. Health and demographic surveillance is a response to the lack of a valid information base that can provide high-quality longitudinal data on population dynamics, health, and social change to inform policy and practice. Design and measurement procedures: Continuous demographic monitoring of an entire…
Returning home to die
Aim: To examine the hypothesis that circular labour migrants who become seriously ill while living away from home return to their rural homes to convalesce and possibly to die. Methods: Drawing on longitudinal data collected by the Agincourt health and demographic surveillance system in rural northeastern South Africa between 1995 and 2004, discrete time event history analysis is used to estimate the likelihood of dying for residents, short-term …
Improving public health training and research capacity in Africa
BACKGROUND: Research training for public health professionals is key to the future of public health and policy in Africa. A growing number of schools of public health are connected to health and socio-demographic surveillance system field sites in developing countries, in Africa and Asia in particular. Linking training programs with these sites provides important opportunities to improve training, build local research capacity, foreground local h…
Probabilistic Projections of the Total Fertility Rate for All Countries
We describe a Bayesian projection model to produce country-specific projections of the total fertility rate (TFR) for all countries. The model decomposes the evolution of TFR into three phases: pre-transition high fertility, the fertility transition, and post-transition low fertility. The model for the fertility decline builds on the United Nations Population Division’s current deterministic projection methodology, which assumes that fertility wi…
More on the Cohort-Component Model of Population Projection in the Context of HIV/Aids
This article presents an extension of the cohort-component model of population projection (CCMPP) first formulated by Heuveline (2003) that is capable of modeling a population affected by HIV. Heuveline proposes a maximum likelihood approach to estimate the age profile of HIV incidence that produced the HIV epidemics in East Africa during the 1990s. We extend this work by developing the Leslie matrix representation of the CCMPP, which greatly fac…
Profile
The Agincourt health and socio-demographic surveillance system (HDSS), located in rural northeast South Africa close to the Mozambique border, was established in 1992 to support district health systems development led by the post-apartheid ministry of health. The HDSS (90 000 people), based on an annual update of resident status and vital events, now supports multiple investigations into the causes and consequences of complex health, population a…
Strengthening standardised interpretation of verbal autopsy data
BACKGROUND: Verbal autopsy (VA) is the only available approach for determining the cause of many deaths, where routine certification is not in place. Therefore, it is important to use standards and methods for VA that maximise efficiency, consistency and comparability. The World Health Organization (WHO) has led the development of the 2012 WHO VA instrument as a new standard, intended both as a research tool and for routine registration of deaths…
Child Mobility, Maternal Status, and Household Composition in Rural South Africa
This article examines the influence of maternal status, socioeconomic status of the household, and household composition on the mobility of children aged 0–14 in Mpumalanga Province, South Africa, from 1999 to 2008. Using data from the Agincourt Health and Demographic Surveillance System, we found that children whose mothers were temporary migrants, living elsewhere, or dead had higher odds of moving than children whose mothers were coresident. O…
Estimates of Age-Specific Reductions in HIV Prevalence in Uganda
BACKGROUND: Much of our knowledge of the epidemiology and demography of HIV epidemics in Africa is derived from models fit to sparse, non-representative data. These often average over age and other important dimensions, rarely quantify uncertainty, and typically do not impose consistency on the epidemiology and the demography of the population. OBJECTIVE: This work conducts an empirical investigation of the history of the HIV epidemic in Uganda a…
Estimating trends in the total fertility rate with uncertainty using imperfect data
BACKGROUND: Estimating the total fertility rate is challenging for many developing countries because of limited data and varying data quality. A standardized, reproducible approach to produce estimates that include an uncertainty assessment is desired. METHODS: We develop a method to estimate and assess uncertainty in the total fertility rate over time, based on multiple imperfect observations from different data sources, including surveys and ce…
Prevalence of HIV among those 15 and older in rural South Africa
A greater knowledge of the burden of HIV in rural areas of Southern Africa is needed, especially among older adults. We conducted a cross-sectional biomarker survey in the rural South African Agincourt Health and Socio-demographic Surveillance site in 2010-2011 and estimated HIV prevalence and risk factors. Using an age-sex stratified random sample of ages 15+, a total of 5037 (65.7%) of a possible 7662 individuals were located and 4362 (86.6%) c…
The age pattern of increases in mortality affected by HIV
BACKGROUND: We investigate the sex-age-specific changes in the mortality of a prospectively monitored rural population in South Africa. We quantify changes in the age pattern of mortality in a parsimonious way by estimating the eight parameters of the Heligman-Pollard (HP) model of age-specific mortality. In its traditional form this model is difficult to fit and does not account for uncertainty. OBJECTIVE: 1. To quantify changes in the sex-age p…
Migration and the epidemiological transition
BACKGROUND: Migration and urbanization are central to sustainable development and health, but data on temporal trends in defined populations are scarce. Healthy men and women migrate because opportunities for employment and betterment are not equally distributed geographically. The disruption can result in unhealthy exposures and environments and income returns for the origin household. OBJECTIVES: The objectives of the paper are to describe the …
The INDEPTH standard population for low- and middle-income countries, 2013
Crude rates such as the crude death rate are functions of both the age-specific rates and the age composition of a population. However, differences in the age structure between two populations or two time periods can result in specious differences in the corresponding crude rates making direct comparisons between populations or across time inappropriate. Therefore, when comparing crude rates between populations, it is desirable to eliminate or mi…
Male and female sterility in Zambia
BACKGROUND: Population measures of sterility are traditionally constructed for women, despite fertility and sterility being conditions of the couple. Estimates of male sterility provide insight into population-level sterility, and complement estimates based solely on women. OBJECTIVE: This study seeks to estimate male sterility for the Gwembe Tonga of Zambia using male birth histories collected by the Gwembe Tonga Research Project from 1957 to 19…
Cardiometabolic disease risk and HIV status in rural South Africa
Sub-Saharan Africa is facing intersecting epidemics of HIV and hypertension. In this setting, around half the adult population require long-term care for at least one of HIV, hypertension or diabetes. Together with the adverse effects that HIV and its treatment have on lipids, this may have serious implications for the South African health care system. Monitoring of the interaction of HIV, ART use, and cardiometabolic disease is needed at both in…
Bayesian population reconstruction of female populations for less developed and more developed countries
We show that Bayesian population reconstruction, a recent method for estimating past populations by age, works for data of widely varying quality. Bayesian reconstruction simultaneously estimates age-specific population counts, fertility rates, mortality rates, and net international migration flows from fragmentary data, while formally accounting for measurement error. As inputs, Bayesian reconstruction uses initial bias-reduced estimates of stan…
Let's Talk about Sex, Maybe
Researchers are often skeptical of sexual behavior surveys: Respondents may lie or forget details of their intimate lives, and interviewers may exercise authority in how they capture responses. We use data from a 2010-2011 cross-sectional sexual behavior survey in rural South Africa to explore who says what to whom about their sexual lives. Results show an effect of fieldworker age across outcomes: Respondents report "safer," more "responsible" s…
Progression of the epidemiological transition in a rural South African setting
This typical rural South African population is experiencing a protracted epidemiological transition. The intersection and interaction of HIV/AIDS and antiretroviral treatment, non-communicable disease risk factors and complex social and behavioral changes will impact on continued progress in reducing preventable mortality and improving health across the life course. Integrated healthcare planning and program delivery is required to improve access…
Assessing Changes in Household Socioeconomic Status in Rural South Africa, 2001-2013
Population (25 obras) · Medicine (24 obras) · Demography (23 obras) · Sociology (18 obras) · Geography (17 obras) · Environmental health (14 obras) · Economics (13 obras) · Mathematics (11 obras) · Global Maternal and Child Health (10 obras) · Public health (9 obras)