Denzil Fiebig - Academia.edu (original) (raw)
Papers by Denzil Fiebig
Journal of the American Statistical Association, Sep 1, 1986
Social Science Research Network, 2008
A Bayesian analysis is given of a random effects binary probit model that allows for heteroscedas... more A Bayesian analysis is given of a random effects binary probit model that allows for heteroscedasticity. Real examples and simulations illustrate the approach and show that ignoring heteroscedasticity when it is there leads to biased estimates and poor prediction. The computation carried out by Markov chain Monte Carlo simulation is made efficient by generating the parameters in blocks. We use the Deviance Information Criterion for model comparison and evaluate the predictive ability of different models using the Receiving Operating Characteristic curve.
RePEc: Research Papers in Economics, Feb 1, 2010
The percentage of Australians taking up Private Health Insurance (PHI) was in decline following t... more The percentage of Australians taking up Private Health Insurance (PHI) was in decline following the introduction of Medicare in 1984 (PHIAC). To arrest this decline the Australian Government introduced a suite of policies, between 1997 and 2000, to create incentives for Australians to purchase private health insurance. These policies include an increased Medicare levy for those without PHI on high incomes, introduced in 1997, a 30% rebate for private hospital cover (introduced 1998), and the Lifetime Health Cover (LHC) policy where PHI premiums are set at age of entry, increasing for each year older than 30 years (introduced 2000). In 2004 the longitudinal study on Household Income and Labour Dynamics in Australia (HILDA), included a series of questions on private health insurance and hospital use. We used the HILDA data to investigate the demographic, health and income factors related to the PHI decisions, especially around the introduction of the Lifetime Health Cover policy. Specifically we investigate who was most influenced to purchase PHI (specifically hospital cover) in 2000 as a response to the Lifetime Health Cover policy deadline. Are those who have joined PHI since the introduction of LHC different from those who joined prior to LHC? What are the characteristics of those who have dropped PHI since the introduction of LHC? We model the PHI outcomes allowing for heterogeneity of choice and correlation across alternatives. After controlling for other factors, we find that LHC prompted moderately well-off working age adults (30-49 yrs) to purchase before the 2000 deadline. Young singles or couples with no children, and the overseas born were more likely to purchase since 2000, while the relatively less well-off continue to drop PHI in spite of current policy incentives.
Advanced studies in theoretical and applied econometrics, 1992
The maximum entropy (ME) criterion is used to justify three different specifications of distribut... more The maximum entropy (ME) criterion is used to justify three different specifications of distributed lags. For lag distributions in several dimensions, the ME criterion yields a considerable simplification.
Blackwell Publishing Ltd eBooks, Nov 30, 2007
Bayesian Analysis, Sep 1, 2009
Contingent valuation models are used in Economics to value nonmarket goods and can be expressed a... more Contingent valuation models are used in Economics to value nonmarket goods and can be expressed as binary choice regression models with one of the regression coefficients fixed. A method for flexibly estimating the link function of such binary choice model is proposed by using a Dirichlet process mixture prior on the space of all latent variable distributions, instead of the more restricted distributions in earlier papers. The model is estimated using a novel MCMC sampling scheme that avoids the high autocorrelations in the iterates that usually arise when sampling latent variables that are mixtures. The method allows for variable selection and is illustrated using simulated and real data.
AEA Randomized Controlled Trials, May 25, 2023
Social Science Research Network, 2007
It was established as a UTS Centre in February, 2002. The Centre aims to contribute to the develo... more It was established as a UTS Centre in February, 2002. The Centre aims to contribute to the development and application of health economics and health services research through research, teaching and policy support. CHERE's research program encompasses both the theory and application of health economics. The main theoretical research theme pursues valuing benefits, including understanding what individuals value from health and health care, how such values should be measured, and exploring the social values attached to these benefits. The applied research focuses on economic and the appraisal of new programs or new ways of delivering and/or funding services. CHERE's teaching includes introducing clinicians, health services managers, public health professionals and others to health economic principles. Training programs aim to develop practical skills in health economics and health services research. Policy support is provided at all levels of the health care system by undertaking commissioned projects, through the provision of formal and informal advice as well as participation in working parties and committees.
Mathematics and Computers in Simulation, Nov 1, 1995
Social Science & Medicine, Apr 1, 2013
Recent rapid growth in the range of contraceptive products has given women more choice, but also ... more Recent rapid growth in the range of contraceptive products has given women more choice, but also adds complexity to the resultant decision of which product to choose. This paper uses a discrete choice experiment (DCE) to investigate the effect of adverse information and positive promotion on women's stated preferences for prescribed contraceptive products. In November 2007, 527 Australian women aged 18-49 years were recruited from an online panel. Each was randomly allocated to one of three information conditions. The control group only received basic information on contraceptive products. One treatment group also received adverse information on the risks of the combined oral pill. The other group received basic information and promotional material on the vaginal ring, newly introduced into Australia and on the transdermal patch, which is unavailable in Australia. Respondents completed 32 choice sets with 3 product options where each option was described by a product label: either combined pill, minipill, injection, implant, hormonal IUD, hormonal vaginal ring, hormonal transdermal patch or copper IUD; and by the attributes: effect on acne, effect on weight, frequency of administration, contraceptive effectiveness, doctor's recommendation, effect on periods and cost. Women's choices were analysed using a generalized multinomial logit model (G-MNL) and model estimates were used to predict product shares for each information condition. The predictions indicated that adverse information did not affect women's preferences for products relative to only receiving basic information. The promotional material increased women's preferences for the transdermal patch. Women in all groups had a low preference for the vaginal ring which was not improved by promotion. The findings highlight the need for researchers to pay attention to setting the context when conducting DCEs as this can significantly affect results.
Utilities Policy, 1992
ABSTRACT DELMOD is a domestic end-use forecasting and simulation model for the residential electr... more ABSTRACT DELMOD is a domestic end-use forecasting and simulation model for the residential electricity load curve in New South Wales, Australia. For a given scenario it produces profiles for average working and non-working days for a given month. With its detailed representation of the appliance stock and socio-demographic characteristics, and its facilities for investigating conservation effects and weather sensitivity, it is an extremely flexible tool for examining a great variety of future scenarios. The paper outlines the structure of DELMOD, discusses the estimation procedures employed, and presents a range of scenario forecasts produced by the model.
Health Economics, Nov 24, 2010
New contraceptive methods provide greater choice in terms of effectiveness, management of side-ef... more New contraceptive methods provide greater choice in terms of effectiveness, management of side-effects, convenience and frequency of administration and flexibility, but make the decisions about contraception more complex. There are limited data on the factors that determine women's choices among these alternatives, to inform providers about the factors which are most important to women, or to predict uptake of new products. This paper reports on a choice experiment designed to elicit women's preferences in relation to prescribed contraception and to forecast the impact of the introduction of two new products into the Australian market. A generalized multinomial logit model is estimated and used in the simulation exercise. The model forecasts that the hormonal patch would be well received among women, achieving a greater market share than current non-pill products, but the vaginal ring would have limited appeal.
Journal of Health Economics, May 1, 2014
Well-being losses due to care-giving van den Berg,
Binkley (1989) presented Monte Carlo evidence on the relative efficiency of two estimators of the... more Binkley (1989) presented Monte Carlo evidence on the relative efficiency of two estimators of the regression coeffícients in the grouped heteroskedastic model. The alternatlve methods dlffer according to whether the disturbance variances are estimated using residuals from índívidual group regressions or one pooled regression. This note extends this dlscussion, placing partlcular emphasis on the question of computational convenience, and on testing hypotheses and imposing restrictions on varíance parameters. The arguments presented here provide further information on which to base a choice between the alternative methods.
Oxford Research Encyclopedia of Economics and Finance, Apr 26, 2019
Stated preference methods are used to collect individual level data on what respondents say they ... more Stated preference methods are used to collect individual level data on what respondents say they would do when faced with a hypothetical but realistic situation. The hypothetical nature of the data has long been a source of concern amongst researchers as such data stand in contrast to revealed preference data which record the choices made by individuals in actual market situations. But there is considerable support for stated preference methods as they are a cost-effective means of generating data that can be specifically tailored to a research question and, in some cases, such as gauging preferences for a new product or non-market good, there may be no practical alternative source of data. While stated preference data come in many forms, the primary focus in this chapter will be data generated by discrete choice experiments and thus the econometric methods will be those associated with modelling binary and multinominal choices with panel data.
Mathematics and Computers in Simulation, Apr 1, 1992
Economic Record, Mar 1, 2007
Applied Mathematics and Computation, Apr 1, 1984
In the context of estimating a covariance matrix, the problem of undersized samples occurs when t... more In the context of estimating a covariance matrix, the problem of undersized samples occurs when the number of sample observations is less than the number of variables. One possible solution to such problems its they arise in the estimation of covariance matrices, and more general multivariate analyses, is provided by the maximum-entropy (ME) distribution and its covariance matrix. This paper addresses two questions that are often posed with regard to the ME covariancc matrix: (1) Does the procedure involve a heavy computational burden? (2) How does it relate to the solutions provided by generalized inverses? *MGR Working Paper #M8305. The author would like to acknowledge the assistance and encouragement of J. Hirschberg and H. Theil.
The Patient: Patient-Centered Outcomes Research, Oct 13, 2016
Within a generation, empirical researchers have experienced unprecedented increases in the availa... more Within a generation, empirical researchers have experienced unprecedented increases in the availability of data. 'Big data' has arrived with considerable hype and a sense that these are dramatic shifts in the research environment that have wide-reaching implications across many disciplines. There is no doubt that the analysis of new and varied sources of data currently available to researchers in health have the potential to better measure, monitor and describe health outcomes of patients and to uncover interesting patterns in how patients respond to treatments and interact with the health system. What is less clear is whether answers are readily available to more nuanced and substantive research questions. Here, the data-rich environment needs to be complemented by considerable research effort developing novel research designs and generating new and improved methods of analysis. Importantly, this will require researchers to be able to combine data from multiple sources and to be pro-active in data collection.
The journal of the economics of ageing, Oct 1, 2020
The present study examines the reciprocal relationship between Internet use and cognitive functio... more The present study examines the reciprocal relationship between Internet use and cognitive function over time among middle-aged and older populations in China. We use data from the first three waves of the China Health and Retirement Longitudinal Study (CHARLS), where participants provided information on Internet use and cognitive function measures at the baseline in 2011 as well as two follow-ups in 2013 and 2015. Cross-lagged panel models were fitted to test the reciprocal association over these four years. Middle-aged and older individuals with higher cognitive function were more likely to be regular Internet users. After controlling for the effects of cognition two years prior, Internet users tended to score higher on cognitive tests than non-users. These findings survived across alternative subsamples and model specifications. Our results suggest that cognitive decline in later life may explain the lower technology adoption rate among older individuals. Meanwhile, Internet use could serve as a protective factor against cognitive decline in mid-life and older adulthood.
Journal of the American Statistical Association, Sep 1, 1986
Social Science Research Network, 2008
A Bayesian analysis is given of a random effects binary probit model that allows for heteroscedas... more A Bayesian analysis is given of a random effects binary probit model that allows for heteroscedasticity. Real examples and simulations illustrate the approach and show that ignoring heteroscedasticity when it is there leads to biased estimates and poor prediction. The computation carried out by Markov chain Monte Carlo simulation is made efficient by generating the parameters in blocks. We use the Deviance Information Criterion for model comparison and evaluate the predictive ability of different models using the Receiving Operating Characteristic curve.
RePEc: Research Papers in Economics, Feb 1, 2010
The percentage of Australians taking up Private Health Insurance (PHI) was in decline following t... more The percentage of Australians taking up Private Health Insurance (PHI) was in decline following the introduction of Medicare in 1984 (PHIAC). To arrest this decline the Australian Government introduced a suite of policies, between 1997 and 2000, to create incentives for Australians to purchase private health insurance. These policies include an increased Medicare levy for those without PHI on high incomes, introduced in 1997, a 30% rebate for private hospital cover (introduced 1998), and the Lifetime Health Cover (LHC) policy where PHI premiums are set at age of entry, increasing for each year older than 30 years (introduced 2000). In 2004 the longitudinal study on Household Income and Labour Dynamics in Australia (HILDA), included a series of questions on private health insurance and hospital use. We used the HILDA data to investigate the demographic, health and income factors related to the PHI decisions, especially around the introduction of the Lifetime Health Cover policy. Specifically we investigate who was most influenced to purchase PHI (specifically hospital cover) in 2000 as a response to the Lifetime Health Cover policy deadline. Are those who have joined PHI since the introduction of LHC different from those who joined prior to LHC? What are the characteristics of those who have dropped PHI since the introduction of LHC? We model the PHI outcomes allowing for heterogeneity of choice and correlation across alternatives. After controlling for other factors, we find that LHC prompted moderately well-off working age adults (30-49 yrs) to purchase before the 2000 deadline. Young singles or couples with no children, and the overseas born were more likely to purchase since 2000, while the relatively less well-off continue to drop PHI in spite of current policy incentives.
Advanced studies in theoretical and applied econometrics, 1992
The maximum entropy (ME) criterion is used to justify three different specifications of distribut... more The maximum entropy (ME) criterion is used to justify three different specifications of distributed lags. For lag distributions in several dimensions, the ME criterion yields a considerable simplification.
Blackwell Publishing Ltd eBooks, Nov 30, 2007
Bayesian Analysis, Sep 1, 2009
Contingent valuation models are used in Economics to value nonmarket goods and can be expressed a... more Contingent valuation models are used in Economics to value nonmarket goods and can be expressed as binary choice regression models with one of the regression coefficients fixed. A method for flexibly estimating the link function of such binary choice model is proposed by using a Dirichlet process mixture prior on the space of all latent variable distributions, instead of the more restricted distributions in earlier papers. The model is estimated using a novel MCMC sampling scheme that avoids the high autocorrelations in the iterates that usually arise when sampling latent variables that are mixtures. The method allows for variable selection and is illustrated using simulated and real data.
AEA Randomized Controlled Trials, May 25, 2023
Social Science Research Network, 2007
It was established as a UTS Centre in February, 2002. The Centre aims to contribute to the develo... more It was established as a UTS Centre in February, 2002. The Centre aims to contribute to the development and application of health economics and health services research through research, teaching and policy support. CHERE's research program encompasses both the theory and application of health economics. The main theoretical research theme pursues valuing benefits, including understanding what individuals value from health and health care, how such values should be measured, and exploring the social values attached to these benefits. The applied research focuses on economic and the appraisal of new programs or new ways of delivering and/or funding services. CHERE's teaching includes introducing clinicians, health services managers, public health professionals and others to health economic principles. Training programs aim to develop practical skills in health economics and health services research. Policy support is provided at all levels of the health care system by undertaking commissioned projects, through the provision of formal and informal advice as well as participation in working parties and committees.
Mathematics and Computers in Simulation, Nov 1, 1995
Social Science & Medicine, Apr 1, 2013
Recent rapid growth in the range of contraceptive products has given women more choice, but also ... more Recent rapid growth in the range of contraceptive products has given women more choice, but also adds complexity to the resultant decision of which product to choose. This paper uses a discrete choice experiment (DCE) to investigate the effect of adverse information and positive promotion on women's stated preferences for prescribed contraceptive products. In November 2007, 527 Australian women aged 18-49 years were recruited from an online panel. Each was randomly allocated to one of three information conditions. The control group only received basic information on contraceptive products. One treatment group also received adverse information on the risks of the combined oral pill. The other group received basic information and promotional material on the vaginal ring, newly introduced into Australia and on the transdermal patch, which is unavailable in Australia. Respondents completed 32 choice sets with 3 product options where each option was described by a product label: either combined pill, minipill, injection, implant, hormonal IUD, hormonal vaginal ring, hormonal transdermal patch or copper IUD; and by the attributes: effect on acne, effect on weight, frequency of administration, contraceptive effectiveness, doctor's recommendation, effect on periods and cost. Women's choices were analysed using a generalized multinomial logit model (G-MNL) and model estimates were used to predict product shares for each information condition. The predictions indicated that adverse information did not affect women's preferences for products relative to only receiving basic information. The promotional material increased women's preferences for the transdermal patch. Women in all groups had a low preference for the vaginal ring which was not improved by promotion. The findings highlight the need for researchers to pay attention to setting the context when conducting DCEs as this can significantly affect results.
Utilities Policy, 1992
ABSTRACT DELMOD is a domestic end-use forecasting and simulation model for the residential electr... more ABSTRACT DELMOD is a domestic end-use forecasting and simulation model for the residential electricity load curve in New South Wales, Australia. For a given scenario it produces profiles for average working and non-working days for a given month. With its detailed representation of the appliance stock and socio-demographic characteristics, and its facilities for investigating conservation effects and weather sensitivity, it is an extremely flexible tool for examining a great variety of future scenarios. The paper outlines the structure of DELMOD, discusses the estimation procedures employed, and presents a range of scenario forecasts produced by the model.
Health Economics, Nov 24, 2010
New contraceptive methods provide greater choice in terms of effectiveness, management of side-ef... more New contraceptive methods provide greater choice in terms of effectiveness, management of side-effects, convenience and frequency of administration and flexibility, but make the decisions about contraception more complex. There are limited data on the factors that determine women's choices among these alternatives, to inform providers about the factors which are most important to women, or to predict uptake of new products. This paper reports on a choice experiment designed to elicit women's preferences in relation to prescribed contraception and to forecast the impact of the introduction of two new products into the Australian market. A generalized multinomial logit model is estimated and used in the simulation exercise. The model forecasts that the hormonal patch would be well received among women, achieving a greater market share than current non-pill products, but the vaginal ring would have limited appeal.
Journal of Health Economics, May 1, 2014
Well-being losses due to care-giving van den Berg,
Binkley (1989) presented Monte Carlo evidence on the relative efficiency of two estimators of the... more Binkley (1989) presented Monte Carlo evidence on the relative efficiency of two estimators of the regression coeffícients in the grouped heteroskedastic model. The alternatlve methods dlffer according to whether the disturbance variances are estimated using residuals from índívidual group regressions or one pooled regression. This note extends this dlscussion, placing partlcular emphasis on the question of computational convenience, and on testing hypotheses and imposing restrictions on varíance parameters. The arguments presented here provide further information on which to base a choice between the alternative methods.
Oxford Research Encyclopedia of Economics and Finance, Apr 26, 2019
Stated preference methods are used to collect individual level data on what respondents say they ... more Stated preference methods are used to collect individual level data on what respondents say they would do when faced with a hypothetical but realistic situation. The hypothetical nature of the data has long been a source of concern amongst researchers as such data stand in contrast to revealed preference data which record the choices made by individuals in actual market situations. But there is considerable support for stated preference methods as they are a cost-effective means of generating data that can be specifically tailored to a research question and, in some cases, such as gauging preferences for a new product or non-market good, there may be no practical alternative source of data. While stated preference data come in many forms, the primary focus in this chapter will be data generated by discrete choice experiments and thus the econometric methods will be those associated with modelling binary and multinominal choices with panel data.
Mathematics and Computers in Simulation, Apr 1, 1992
Economic Record, Mar 1, 2007
Applied Mathematics and Computation, Apr 1, 1984
In the context of estimating a covariance matrix, the problem of undersized samples occurs when t... more In the context of estimating a covariance matrix, the problem of undersized samples occurs when the number of sample observations is less than the number of variables. One possible solution to such problems its they arise in the estimation of covariance matrices, and more general multivariate analyses, is provided by the maximum-entropy (ME) distribution and its covariance matrix. This paper addresses two questions that are often posed with regard to the ME covariancc matrix: (1) Does the procedure involve a heavy computational burden? (2) How does it relate to the solutions provided by generalized inverses? *MGR Working Paper #M8305. The author would like to acknowledge the assistance and encouragement of J. Hirschberg and H. Theil.
The Patient: Patient-Centered Outcomes Research, Oct 13, 2016
Within a generation, empirical researchers have experienced unprecedented increases in the availa... more Within a generation, empirical researchers have experienced unprecedented increases in the availability of data. 'Big data' has arrived with considerable hype and a sense that these are dramatic shifts in the research environment that have wide-reaching implications across many disciplines. There is no doubt that the analysis of new and varied sources of data currently available to researchers in health have the potential to better measure, monitor and describe health outcomes of patients and to uncover interesting patterns in how patients respond to treatments and interact with the health system. What is less clear is whether answers are readily available to more nuanced and substantive research questions. Here, the data-rich environment needs to be complemented by considerable research effort developing novel research designs and generating new and improved methods of analysis. Importantly, this will require researchers to be able to combine data from multiple sources and to be pro-active in data collection.
The journal of the economics of ageing, Oct 1, 2020
The present study examines the reciprocal relationship between Internet use and cognitive functio... more The present study examines the reciprocal relationship between Internet use and cognitive function over time among middle-aged and older populations in China. We use data from the first three waves of the China Health and Retirement Longitudinal Study (CHARLS), where participants provided information on Internet use and cognitive function measures at the baseline in 2011 as well as two follow-ups in 2013 and 2015. Cross-lagged panel models were fitted to test the reciprocal association over these four years. Middle-aged and older individuals with higher cognitive function were more likely to be regular Internet users. After controlling for the effects of cognition two years prior, Internet users tended to score higher on cognitive tests than non-users. These findings survived across alternative subsamples and model specifications. Our results suggest that cognitive decline in later life may explain the lower technology adoption rate among older individuals. Meanwhile, Internet use could serve as a protective factor against cognitive decline in mid-life and older adulthood.