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1.
Exp Econ ; 25(3): 795-823, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35018135

RESUMO

The COVID-19 pandemic presents a remarkable opportunity to put to work all of the research that has been undertaken in past decades on the elicitation and structural estimation of subjective belief distributions as well as preferences over atemporal risk, patience, and intertemporal risk. As contributors to elements of that research in laboratories and the field, we drew together those methods and applied them to an online, incentivized experiment in the United States. We have two major findings. First, the atemporal risk premium during the COVID-19 pandemic appeared to change significantly compared to before the pandemic, consistent with theoretical results of the effect of increased background risk on foreground risk attitudes. Second, subjective beliefs about the cumulative level of deaths evolved dramatically over the period between May and November 2020, a volatile one in terms of the background evolution of the pandemic. Supplementary Information: The online version contains supplementary material available at 10.1007/s10683-021-09738-3.

2.
Methods ; 195: 103-112, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33838269

RESUMO

Subjective belief elicitation about uncertain events has a long lineage in the economics and statistics literatures. Recent developments in the experimental elicitation and statistical estimation of subjective belief distributions allow inferences about whether these beliefs are biased relative to expert opinion, and the confidence with which they are held. Beliefs about COVID-19 prevalence and mortality interact with risk management efforts, so it is important to understand relationships between these beliefs and publicly disseminated statistics, particularly those based on evolving epidemiological models. The pandemic provides a unique setting over which to bracket the range of possible COVID-19 prevalence and mortality outcomes given the proliferation of estimates from epidemiological models. We rely on the epidemiological model produced by the Institute for Health Metrics and Evaluation together with the set of epidemiological models summarised by FiveThirtyEight to bound prevalence and mortality outcomes for one-month, and December 1, 2020 time horizons. We develop a new method to partition these bounds into intervals, and ask subjects to place bets on these intervals, thereby revealing their beliefs. The intervals are constructed such that if beliefs are consistent with epidemiological models, subjects are best off betting the same amount on every interval. We use an incentivised experiment to elicit beliefs about COVID-19 prevalence and mortality from 598 students at Georgia State University, using six temporally-spaced waves between May and November 2020. We find that beliefs differ markedly from epidemiological models, which has implications for public health communication about the risks posed by the virus.


Assuntos
COVID-19/mortalidade , COVID-19/psicologia , Cultura , Tomada de Decisões , Modelo de Crenças de Saúde , Inquéritos e Questionários/normas , COVID-19/epidemiologia , Tomada de Decisões/fisiologia , Humanos , Mortalidade/tendências , Prevalência
3.
Am J Drug Alcohol Abuse ; 46(1): 109-119, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31290698

RESUMO

Background: Contingency management (CM) is an empirically supported behavioral treatment for tobacco use, but its efficacy with university student smokers in a developing country is unknown. Objectives: We evaluate a randomized controlled trial of a CM smoking cessation program conducted on a sample of treatment-seeking student smokers at the University of Cape Town.Methods: The study included a recruitment period, a 6-week intervention period, and a 6-month follow-up period. Subjects in the control group (information and monitoring; n = 47, 76% male) were given information to help them quit smoking and had their quit attempt monitored, receiving R50 ($8) at each assessment. Subjects in the treatment group (information and monitoring, plus CM; n = 40, 80% male) could additionally earn R150 ($24) in abstinence-contingent incentives at each assessment. Outcome variables: 7-day point-prevalence abstinence at 6 months and at the end of the intervention period, and a repeated measure of smoking intensity of non-abstinent subjects.Results: CM had no long-term effect on abstinence at 6 months but had a marked and statistically significant effect on the likelihood of abstinence by the end of the intervention period (p < .001). In addition, while CM did not affect smoking intensity, participation in the program decreased the average number of cigarettes smoked per day by non-abstainers (p < .001).Conclusions: The CM program was efficacious in promoting abstinence amongst treatment-seeking university students in a developing country but only while incentives were in place. Future research should focus on promoting continuous abstinence with this target sample.


Assuntos
Motivação , Abandono do Hábito de Fumar , Terapia Comportamental/economia , Terapia Comportamental/métodos , Fumar Cigarros/terapia , Países em Desenvolvimento , Feminino , Humanos , Masculino , África do Sul/epidemiologia , Estudantes , Universidades , Adulto Jovem
4.
J Gambl Stud ; 31(3): 679-94, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24927870

RESUMO

We investigate the extent to which problem gambling in a recent South African sample, as measured by the Problem Gambling Severity Index (PGSI), is comorbid with depression, anxiety and substance abuse. Data are from the 2010 South African National Urban Prevalence Study of Gambling Behavior. A representative sample of the urban adult population in South Africa (N = 3,000). Responses to the 9-item PGSI and ratings on the Beck Depression Index, the Beck Anxiety Inventory, and the World Health Organization Alcohol, Smoking and Substance Involvement Screening Tool (WHO ASSIST). Cross tabulations and Chi square analyses along with logistic regression analyses with and without controls for socio-demographic and/or socio-economic variables were used to identify comorbidities. The prevalence of depression, anxiety, alcohol and substance use were clearly higher among the sample at risk for problem gambling. Black African racial status and living in areas characterized by migrant mining workers was associated with increased risk of problem gambling and comorbidities. There is strong evidence that findings of comorbidities between pathological gambling and depression, anxiety and substance abuse in developed countries generalize to the developing country of South Africa. Historical context, however, gives those comorbidities a unique demographic distribution.


Assuntos
Ansiedade/psicologia , Depressão/psicologia , Jogo de Azar/psicologia , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , População Urbana/estatística & dados numéricos , Adulto , Ansiedade/epidemiologia , Comorbidade , Estudos Transversais , Depressão/epidemiologia , Feminino , Jogo de Azar/epidemiologia , Humanos , Masculino , Prevalência , Fatores de Risco , África do Sul/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Adulto Jovem
5.
J Gambl Stud ; 29(3): 377-92, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22711182

RESUMO

We investigate the question whether problem gambling (PG) in a recent South African sample, as measured by the Problem Gambling Severity Index (PGSI), is dimensional or categorical. We use two taxometric procedures, Mean Above Minus Below A Cut (MAMBAC) and Maxim Covariance (MAXCOV), to investigate the taxonic structure of PG as constructed by the PGSI. Data are from the 2010 South African National Urban Prevalence Study of Gambling Behavior. A representative sample of the urban adult population in South Africa (N = 3,000). Responses are to the 9 item PGSI. MAMBAC provided positive but modest evidence that PG as measured by the PGSI was taxonic. MAXCOV pointed more strongly to the same conclusion. These analyses also provide evidence that a PGSI cutoff score of 10 rather than the standard 8 may be called for. PG as constructed by the PGSI may best be thought of as categorical, but further studies with more theory based measurements are needed to determine whether this holds in a wider range of samples and for other screens. A higher cutoff score may be called for on the PGSI when it is used for research purposes to avoid false positives.


Assuntos
Comportamento Aditivo/classificação , Jogo de Azar/classificação , Jogo de Azar/psicologia , População Urbana , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Índice de Gravidade de Doença , África do Sul
6.
Assessment ; 19(2): 167-75, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21856717

RESUMO

Increases in the availability of gambling heighten the need for a short screening measure of problem gambling. The Problem Gambling Severity Index (PGSI) is a brief measure that allows for the assessment of characteristics of gambling behavior and severity and its consequences. The authors evaluate the psychometric properties of the PGSI using item response theory methods in a representative sample of the urban adult population in South Africa (N = 3,000). The PGSI items were evaluated for differential item functioning (DIF) due to language translation. DIF was not detected. The PGSI was found to be unidimensional, and use of the nominal categories model provided additional information at higher values of the underlying construct relative to a simpler binary model. This study contributes to the growing literature supporting the PGSI as the screen of choice for assessing gambling problems in the general population.


Assuntos
Jogo de Azar/psicologia , Transtornos da Personalidade/psicologia , Testes de Personalidade , Teoria Psicológica , Psicometria , Adulto , Distribuição de Qui-Quadrado , Feminino , Jogo de Azar/diagnóstico , Humanos , Masculino , Transtornos da Personalidade/diagnóstico , Índice de Gravidade de Doença , África do Sul
8.
Perspect Biol Med ; 51(3): 367-78, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18723941

RESUMO

This article applies general ideas from contemporary philosophy of science--chief among them that much good science proceeds without theories and laws--to the science of medicine. I claim that traditional philosophical debates over the nature of disease make demands on medicine that are mistaken. I demonstrate this philosophical error by applying the perspective of the philosophy of science to understanding the nature of disease in two concrete cases, cancer and depression. I first argue that cancer research produces various kinds of piecemeal causal explanation and does so without any well-developed theory of normal and malignant functioning, despite the rhetoric of some leading cancer researchers. I then defuse doubts about the scientific status of psychiatry, by demonstrating that it is not necessary to have a theory of normal functioning in order to understand and treat depression.


Assuntos
Teoria da Decisão , Depressão , Neoplasias , Filosofia Médica , Projetos de Pesquisa , Humanos , Modelos Biológicos , Psiquiatria
9.
Account Res ; 12(4): 263-80, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16578917

RESUMO

PURPOSE: The overall purposes of this article are to report the development of a survey instrument, Scientific Misconduct Questionnaire-Revised (SMQ-R) that elicits the perceptions of research coordinators managing clinical trials about the various aspects of scientific misconduct and to present psychometric analyses for the SMQ-R. METHODS: A panel of five researchers and research coordinators reviewed the original SMQ (Rankin and Esteeves, 1997) and suggested an additional 42 items based on the review of the literature and their own experiences in research. The SMQ-Revised (SMQ-R) consists of 68 closed-choice items in six sections and one section with 12 open-ended questions. The SMQ-R was sent to 5302 persons who were members of the Association for Clinical Research Professionals (ACRP) or subscribers to Research Practitioner, published by the Center for Clinical Research Practice (CCRP). FINDINGS: Internal consistency of subscales was assessed with Cronbach's alpha and ranged from .83 to .84. Confirmatory factor analysis was used to test construct validity of the instrument subscales. The factor structure was assessed with the principal factors method, using the squared multiple correlations as initial communality estimates followed by varimax (orthogonal) or biquartimax (oblique) rotations. Analyses revealed five distinct factors among three subscales. Construct validity for the SMQ-R was also assessed by testing hypothesized relationships using the known groups approach. CONCLUSION: The current effort demonstrated the usefulness of the SMQ-R in obtaining information from a national sample of experienced research coordinators about their perceptions of the prevalence of different types of scientific misconduct and of factors that influence the occurrence of misconduct. The psychometric evaluation of the SMQ-R suggests good internal consistency for most subscales and suggests adequate construct validity of the instrument as a whole. The analyses also suggest that further refinement of the instrument for future studies is warranted.


Assuntos
Psicometria , Má Conduta Científica , Inquéritos e Questionários/normas , Atitude , Pesquisa Biomédica/ética , Humanos , Reprodutibilidade dos Testes , Pesquisadores/psicologia , Má Conduta Científica/psicologia
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