随机模型在零售顾客未来经济价值估计中的应用

零售顾客的经济价值是由购买次数和平均购买金额共同决定的。本文采用NBD模型来拟合购买次数,用gamma-gamma模型来拟合平均购买金额。基于贝叶斯原理,在给定过去购买行为条件下我们可以计算顾客未来购买次数和平均购买金额的期望值,顾客的未来经济价值就是这两个期望值的乘积。本文应用上述随机模型对一家零售企业的顾客积分卡数据进行了实证分析,结果表明该模型不仅可以比较准确地拟合顾客购买次数和购买金额数据,而且可以对顾客未来价值进行较为准确的预测。该模型方法对于零售企业加强顾客分析,提高顾客管理水平有很大的价值。     

Diminishing Willingness to Pay per Quality‐Adjusted Life Year: Valuing Acute Foodborne Illness

We design and conduct a stated‐preference survey to estimate willingness to pay (WTP) to reduce foodborne risk of acute illness and to test whether WTP is proportional to the corresponding gain in expected quality‐adjusted life years (QALYs). If QALYs measure utility for health, then economic theory requires WTP to be nearly proportional to changes in both health quality and duration of illness and WTP could be estimated by multiplying the expected change in QALYs by an appropriate monetary value. WTP is elicited using double‐bounded, dichotomous‐choice questions in which respondents (randomly selected from the U.S. general adult population, n = 2,858) decide whether to purchase a more expensive food to reduce the risk of foodborne illness. Health risks vary by baseline probability of illness, reduction in probability, duration and severity of illness, and conditional probability of mortality. The expected gain in QALYs is calculated using respondent‐assessed decrements in health‐related quality of life if ill combined with the duration of illness and reduction in probability specified in the survey. We find sharply diminishing marginal WTP for severity and duration of illness prevented. Our results suggest that individuals do not have a constant rate of WTP per QALY, which implies that WTP cannot be accurately estimated by multiplying the change in QALYs by an appropriate monetary value.     

Use of Quality-Adjusted Life Year Weights with Dose-Response Models for Public Health Decisions: A Case Study of the Risks and Benefits of Fish Consumption

Risks associated with toxicants in food are often controlled by exposure reduction. When exposure recommendations are developed for foods with both harmful and beneficial qualities, however, they must balance the associated risks and benefits to maximize public health. Although quantitative methods are commonly used to evaluate health risks, such methods have not been generally applied to evaluating the health benefits associated with environmental exposures. A quantitative method for risk-benefit analysis is presented that allows for consideration of diverse health endpoints that differ in their impact (i.e., duration and severity) using dose-response modeling weighted by quality-adjusted life years saved. To demonstrate the usefulness of this method, the risks and benefits of fish consumption are evaluated using a single health risk and health benefit endpoint. Benefits are defined as the decrease in myocardial infarction mortality resulting from fish consumption, and risks are defined as the increase in neurodevelopmental delay (i.e., talking) resulting from prenatal methylmercury exposure. Fish consumption rates are based on information from Washington State. Using the proposed framework, the net health impact of eating fish is estimated in either a whole population or a population consisting of women of childbearing age and their children. It is demonstrated that across a range of fish methylmercury concentrations (0-1 ppm) and intake levels (0-25 g/day), individuals would have to weight the neurodevelopmental effects 6 times more (in the whole population) or 250 times less (among women of child-bearing age and their children) than the myocardial infarction benefits in order to be ambivalent about whether or not to consume fish. These methods can be generalized to evaluate the merits of other public health and risk management programs that involve trade-offs between risks and benefits.     

Examining Consumer Behavior Toward Genetically Modified (GM) Food in Britain

This study examined behavior toward genetically modified (GM) food in a British community-based sample. We used an equivalent gain task in which participants actually received the options they chose to encourage truthful responding. In conjunction with this, theory of planned behavior (TPB) components were evaluated so as to examine the relative importance of behavioral influences in this domain. Here, the TPB was extended to include additional components to measure self-identity, moral norms, and emotional involvement. Results indicated that the monetary amounts participants accepted in preference to GM food were significantly lower than those accepted in preference to non-GM food. However, the vast majority of participants were indifferent between GM and non-GM food options. All TPB components significantly predicted behavioral intentions to try GM food, with attitudes toward GM being the strongest predictor. Self-identity and emotional involvement were also found to be significant predictors of behavioral intentions but moral norms were not. In addition, behavioral intentions significantly predicted behavior; however, PBC did not. An additional measure of participants' propensity to respond in a socially desirable manner indicated that our results were not influenced by self-presentation issues, giving confidence to our findings. Overall, it appears that the majority of participants (74.5%) would purchase GM food at some price.     

Risk‐Based Decision Making for Reoccupation of Contaminated Areas Following a Wide‐Area Anthrax Release

This article presents an analysis of postattack response strategies to mitigate the risks of reoccupying contaminated areas following a release of Bacillus anthracis spores (the bacterium responsible for causing anthrax) in an urban setting. The analysis is based on a hypothetical attack scenario in which individuals are exposed to B. anthracis spores during an initial aerosol release and then placed on prophylactic antibiotics that successfully protect them against the initial aerosol exposure. The risk from reoccupying buildings contaminated with spores due to their reaerosolization and inhalation is then evaluated. The response options considered include: decontamination of the buildings, vaccination of individuals reoccupying the buildings, extended evacuation of individuals from the contaminated buildings, and combinations of these options. The study uses a decision tree to estimate the costs and benefits of alternative response strategies across a range of exposure risks. Results for best estimates of model inputs suggest that the most cost‐effective response for high‐risk scenarios (individual chance of infection exceeding 11%) consists of evacuation and building decontamination. For infection risks between 4% and 11%, the preferred option is to evacuate for a short period, vaccinate, and then reoccupy once the vaccine has taken effect. For risks between 0.003% and 4%, the preferred option is to vaccinate only. For risks below 0.003%, none of the mitigation actions have positive expected monetary benefits. A sensitivity analysis indicates that for high‐infection‐likelihood scenarios, vaccination is recommended in the case where decontamination efficacy is less than 99.99%.     

An Agent‐Based Model for Pathogen Persistence and Cross‐Contamination Dynamics in a Food Facility

We used an agent‐based modeling (ABM) framework and developed a mathematical model to explain the complex dynamics of microbial persistence and spread within a food facility and to aid risk managers in identifying effective mitigation options. The model explicitly considered personal hygiene practices by food handlers as well as their activities and simulated a spatially explicit dynamic system representing complex interaction patterns among food handlers, facility environment, and foods. To demonstrate the utility of the model in a decision‐making context, we created a hypothetical case study and used it to compare different risk mitigation strategies for reducing contamination and spread of Listeria monocytogenes in a food facility. Model results indicated that areas with no direct contact with foods (e.g., loading dock and restroom) can serve as contamination niches and recontaminate areas that have direct contact with food products. Furthermore, food handlers’ behaviors, including, for example, hygiene and sanitation practices, can impact the persistence of microbial contamination in the facility environment and the spread of contamination to prepared foods. Using this case study, we also demonstrated benefits of an ABM framework for addressing food safety in a complex system in which emergent system‐level responses are predicted using a bottom‐up approach that observes individual agents (e.g., food handlers) and their behaviors. Our model can be applied to a wide variety of pathogens, food commodities, and activity patterns to evaluate efficacy of food‐safety management practices and quantify contamination reductions associated with proposed mitigation strategies in food facilities.     

Consumer Responses to Integrated Risk‐Benefit Information Associated with the Consumption of Food

The risk analysis of the health impact of foods is increasingly focused on integrated risk‐benefit assessment, which will also need to be communicated to consumers. It therefore becomes important to understand how consumers respond to integrated risk‐benefit information. Quality‐adjusted‐life‐years (QALYs) is one measure that can be used to assess the balance between risks and benefits associated with a particular food. The effectiveness of QALYs for communicating both positive and negative health effects associated with food consumption to consumers was examined, using a 3 × 2 experiment varying information about health changes in terms of QALYs associated with the consumption of fish (n = 325). The effect of this information on consumer perceptions of the usefulness of QALYs for describing health effects, on risk and benefit perceptions, attitudes, and intentions to consume fish was examined. Results demonstrated that consumers perceived QALYs as useful for communicating health effects associated with food consumption. QALYs communicated as a net effect were preferred for food products associated with negative net effects on health, while separate communication of both risks and benefits may be preferred for food products associated with positive or zero net health effects. Information about health changes in terms of QALYs facilitated informed decision making by consumers, as indicated by the impact on risk and benefit perceptions as intended by the information. The impact of this information on actual food consumption choices merits further investigation.     

GM Foods and the Misperception of Risk Perception

Public opposition to genetically modified (GM) food and crops is widely interpreted as the result of the public's misperception of the risks. With scientific assessment pointing to no unique risks from GM crops and foods, a strategy of accurate risk communication from trusted sources has been advocated. This is based on the assumption that the benefits of GM crops and foods are self-evident. Informed by the interpretation of some qualitative interviews with lay people, we use data from the Eurobarometer survey on biotechnology to explore the hypothesis that it is not so much the perception of risks as the absence of benefits that is the basis of the widespread rejection of GM foods and crops by the European public. Some respondents perceive both risks and benefits, and may be trading off these attributes along the lines of a rational choice model. However, for others, one attribute-benefit-appears to dominate their judgments: the lexicographic heuristic. For these respondents, their perception of risk is of limited importance in the formation of attitudes toward GM food and crops. The implication is that the absence of perceived benefits from GM foods and crops calls into question the relevance of risk communication strategies for bringing about change in public opinion.     

A Risk Assessment of Campylobacteriosis and Salmonellosis Linked to Chicken Meals Prepared in Households in Dakar,Senegal

We used a quantitative microbiological risk assessment model to describe the risk of Campylobacter and Salmonella infection linked to chicken meals prepared in households in Dakar, Senegal. The model uses data collected specifically for this study, such as the prevalence and level of bacteria on the neck skin of chickens bought in Dakar markets, time‐temperature profiles recorded from purchase to consumption, an observational survey of meal preparation in private kitchens, and detection and enumeration of pathogens on kitchenware and cooks’ hands. Thorough heating kills all bacteria present on chicken during cooking, but cross‐contamination of cooked chicken or ready‐to‐eat food prepared for the meal via kitchenware and cooks’ hands leads to a high expected frequency of pathogen ingestion. Additionally, significant growth of Salmonella is predicted during food storage at ambient temperature before and after meal preparation. These high exposures lead to a high estimated risk of campylobacteriosis and/or salmonellosis in Dakar households. The public health consequences could be amplified by the high level of antimicrobial resistance of Salmonella and Campylobacter observed in this setting. A significant decrease in the number of ingested bacteria and in the risk could be achieved through a reduction of the prevalence of chicken contamination at slaughter, and by the use of simple hygienic measures in the kitchen. There is an urgent need to reinforce the hygiene education of food handlers in Senegal.     

Weighing Health Benefit and Health Risk Information when Consuming Sport-Caught Fish

Fish consumers may incur benefits and risks from eating fish. Health advisories issued by states, tribes, and other entities typically include advice about how to limit fish consumption or change other behaviors (e.g., fish cleaning or cooking) to reduce health risks from exposure to contaminants. Eating fish, however, may provide health benefits. Risk communicators and fish consumers have suggested the importance of including risk comparison information, as well as health risk-benefit comparisons in health advisory communications. To improve understanding about how anglers fishing in waters affected by health advisories may respond to such risk-risk or risk-benefit information, we surveyed Lake Ontario (NY, USA) anglers. We interviewed by telephone 4,750 anglers, 2,593 of which had fished Lake Ontario in the past 12 months and were sent a detailed mail questionnaire (1,245 responded). We posed questions varying the magnitude of health risks and health benefits to be gained by fish consumption, and varied the population affected by these risks and benefits (anglers, children, women of childbearing age, and unborn children). Respondents were influenced by health benefit and health risk information. When risks were high, most respondents would eat less fish regardless of the benefit level. When risks were low, the magnitude of change in fish consumption was related to level of benefit. Responses differed depending on the question wording order, that is, whether "risks" were posed before "benefits." For a given risk-benefit level, respondents would give different advice to women of childbearing age versus children, with more conservative advice (eat less fish) provided to women of childbearing age. Respondents appeared to be influenced more strongly by risk-risk comparisons (e.g., risks from other foods vs. risks from fish) than by risk-benefit comparisons (e.g., risks from fish vs. benefits from fish). Risk analysts and risk communicators should improve efforts to include risk-risk and risk-benefit comparisons in communication efforts, and to clarify to whom the health risks and benefits from fish consumption may accrue.     

THE WELL‐BEING OF THE ELDERLY AND WAGE ARREARS IN RUSSIA

About one‐third of households with elderly were not paid their wages during the mid‐1990s in Russia. Applying matching estimations to a nationally representative survey, the study shows that wage arrears had detrimental effects on the well‐being of the elderly in these families. Salaries in households with wage arrears dropped by almost two‐thirds, income fell by more than one‐third, and poverty doubled. Behavioral responses were only partly effective. The net revenue loss amounted to five‐sixths of the wage shock for men, and nine‐tenths of the wage shock for women. The elderly cut back on food expenses by reducing food purchases and adjusting their diet towards cheaper calories, economising on expenses equal to around one‐quarter of the wage reduction. Caloric and protein intakes dropped, although less than income, and the nutritional content of food consumption with regard to vitamins and minerals deteriorated. Wage arrears worsened male health more than female health, even though the decline in income was comparable. Functional limitations rose by 8% for men and 3% for women, and self‐rated health declined by 2.5% for men and 0.5% for women. Old‐age men with arrears were almost twice as likely to die before the next survey round, and functional limitations of surviving men rose by more than 10%. By contrast, there was no impact on the next round's health status of old‐age women. A rich data set is used to discount alternative explanations, including feedback from health to income, other economic factors, health service access, health behavior, and environmental conditions. (JEL: I12, I30, J14, J30)     

Structured expert elicitation about Listeria monocytogenes cross-contamination in the environment of retail deli operations in the United States

Listeria monocytogenes is among the foodborne pathogens with the highest death toll in the United States. Ready‐to‐eat foods contaminated at retail are an important source of infection. Environmental sites in retail deli operations can be contaminated. However, commonly contaminated sites are unlikely to come into direct contact with food and the public health relevance of environmental contamination has remained unclear. To identify environmental sites that may pose a considerable cross‐contamination risk, to elucidate potential transmission pathways, and to identify knowledge gaps, we performed a structured expert elicitation of 41 experts from state regulatory agencies and the food retail industry with practical experience in retail deli operations. Following the “Delphi” method, the elicitation was performed in three consecutive steps: questionnaire, review and discussion of results, second questionnaire. Hands and gloves were identified as important potential contamination sources. However, bacterial transfers to and from hands or gloves represented a major data gap. Experts agreed about transfer probabilities from cutting boards, scales, deli cases, and deli preparation sinks to product, and about transfer probabilities from floor drains, walk‐in cooler floors, and knife racks to food contact surfaces. Comparison of experts' opinions to observational data revealed a tendency among experts with certain demographic characteristics and professional opinions to overestimate prevalence. Experts’ votes clearly clustered into separate groups not defined by place of employment, even though industry experts may have been somewhat overrepresented in one cluster. Overall, our study demonstrates the value and caveats of expert elicitation to identify data gaps and prioritize research efforts.     

Experimental Analysis of Neighborhood Effects

Families, primarily female‐headed minority households with children, living in high‐poverty public housing projects in five U.S. cities were offered housing vouchers by lottery in the Moving to Opportunity program. Four to seven years after random assignment, families offered vouchers lived in safer neighborhoods that had lower poverty rates than those of the control group not offered vouchers. We find no significant overall effects of this intervention on adult economic self‐sufficiency or physical health. Mental health benefits of the voucher offers for adults and for female youth were substantial. Beneficial effects for female youth on education, risky behavior, and physical health were offset by adverse effects for male youth. For outcomes that exhibit significant treatment effects, we find, using variation in treatment intensity across voucher types and cities, that the relationship between neighborhood poverty rate and outcomes is approximately linear.     

Lifestyle habits,substance use and predictors of job burnout in professional working women

Abstract

This study explores differences in self-reported lifestyle habits, substance use (alcohol, drugs and smoking) and predictors of job burnout in a sample of 879 professional working women employed in dental health ofices in a cross-sectional design. Job burnout was measured using the Maslach Burnout Inventory (MBI) and self-reported substance use and lifestyle habits were assessed using the Stress Assessment Profile. Self-reported drinking, smolung and drug use were only modestly correlated with each other in this sample. Employed women with higher levels of drinking reported significantly lower quality overall lifestyle practices, eating/nunition habits, and more frequent use of avoidant coping strategies in the face of work and life hassles compared to non-drinkers. Women who smoked also reported significantly lower overall lifestyle practices and eating/nutrition habits. Those who reported using drugs for recreational purposes reported significantly greater hassles, poorer lifestyle habits, a less hardy outlook on life, and more frequent use of dysfunctional coping strategies. Although women who reported using drugs experienced significantly higher interpersonal burnout (depersonalization) compared to non-drug users, in general, self-reported substance use was not significantly related to job burnout. After controlling for age and psychological distress, perceived stress, type A behaviour, cognitive hardiness and lifestyle habits significantly contributed to predictions of job burnout in multiple regression analyses. Despite methodological limitations, the prevalence of substance use found in this study supports previous research findings. Professional working women who practise poor lifestyle and health habits appear to be at risk of experiencing job burnout.     

Relationships among shiftworker eating habits, eating satisfaction, and self-reported health in a population of US miners

As part of a larger study on the health and safety of shiftworkers in the mining population by the US Bureau of Mines, the association between meal frequency, meal regularity, eating satisfaction and a self-reported health index was examined. Although the link between shiftwork and some health complaints, such as gastrointestinal disorders, has been established, the research needed to understand why this occurs has not been fully undertaken. Specifically, academic nutritional research has substantially ignored the question of how working irregular hours affects the eating behavior of industrial workers such as miners. In this study the eating habits of 101 surface mine workers were studied. It was found that working the day, afternoon/evening, and night-shifts was related to the number of meals eaten on those shifts and to the consistency of timing of those meals. The lowest eating satisfaction levels were reported by those who ate at different times on all shifts and who changed the number of meals eaten per day on each shift. Lowest self-reported health ratings were reported by those who changed the number of meals taken on each shift, rather than by those who ate one, two or three meals per day. These results are discussed in relation to the possible mechanisms contributing to gastrointestinal disorders and to coping mechanisms that could be adopted by shiftworkers.     

Nutrition considerations in food selection

The importance of nutrition consideration to households in food selection is instrumental in the development of information programs to promote public health and to market healthy food. Using a national telephone survey of 2880 U.S. households, this study examines the role and influence of socio-economic characteristics and lifestyle on a household meal planner’s consideration of four dietary components in food selection. Household income, children in households, geographic location, and gender, age, education, and lifestyle of meal planners affected the consideration of dietary components in food selection. The results provide a basis for developing education programs that focus on the particular dietary consideration of identified demographic subgroups.     

Relationships among shiftworker eating habits,eating satisfaction,and self-reported health in a population of US miners

Abstract

As part of a larger study on the health and safety of shiftworkers in the mining population by the US Bureau of Mines, the association between meal frequency, meal regularity, eating satisfaction and a self-reported health index was examined. Although the link between shiftwork and some health complaints, such as gastrointestinal disorders, has been established, the research needed to understand why this occurs has not been fully undertaken. Specifically, academic nutritional research has substantially ignored the question of how working irregular hours affects the eating behavior of industrial workers such as miners. In this study the eating habits of 101 surface mine workers were studied. It was found that working the day, afternoon/evening, and night-shifts was related to the number of meals eaten on those shifts and to the consistency of timing of those meals. The lowest eating satisfaction levels were reported by those who ate at different times on all shifts and who changed the number of meals eaten per day on each shift. Lowest self-reported health ratings were reported by those who changed the number of meals taken on each shift, rather than by those who ate one, two or three meals per day. These results are discussed in relation to the possible mechanisms contributing to gastrointestinal disorders and to coping mechanisms that could be adopted by shiftworkers.     

Import Security: Assessing the Risks of Imported Food

We use data on food import violations from the FDA Operational and Administrative System for Import Support (OASIS) to address rising concerns associated with imported food, quantify import risks by product and by country of origin, and explore the usefulness of OASIS data for risk assessment. In particular, we assess whether there are significant trends in violations, whether import violations can be used to quantify risks by country and by product, and how import risks depend on economic factors of the country of origin. The results show that normalizing import violations by volume of imports provides a meaningful indicator of risk. We then use regression analysis to characterize import risks.  Using this model, we analyze import risks by product type, violation type, and economic factors of the country of origin.  We find that OASIS data are useful in quantifying food import risks, and that the rate of refusals provides a useful decision tool for risk management.  Furthermore, we find that some economic factors are significant indicators of food import risk by country.     

Who benefits from benefits? Empirical research on tangible incentives

Although a broad field of literature on incentive theory exists, economic research on employer-provided tangible goods (hereafter called benefits) is still in its infancy. The empirical study by Oyer (Res Labor Econ 28:429–467, 2008) is one of few exceptions focusing empirically on the dispersion of tangible incentives. In our study, we test some of his findings by drawing on a German data set. We use two waves of the German Socio-Economic Panel data (2006, 2008) to analyze the occurrence of benefits and their effects on employees’ satisfaction. Our results provide evidence for economic as well as psychological explanations. Looking at differences in firms’ and employees’ characteristics we find that cost efficiency concerns, the purpose to signal good working conditions and the aim to ease employees’ effort costs are evident reasons to provide benefits. Furthermore, analyzing the impact of tangible and monetary incentives on satisfaction and employees’ feeling of being acknowledged by employers, we find different motivational effects. Our results support the psychological explanation that benefits are evaluated separately from other monetary wage components and are more likely to express employers’ concern for their employees and recognition of their performance.     

货币供应机制与财政支出的乘数效应——基于DSGE的分析

本文通过构建包括货币供应机制的DSGE模型,分析了中国政府购买支出和公共投资支出的乘数效应,发现两类财政支出对私人消费和私人投资都产生了挤出效应,公共资本的产出弹性低是产生挤出效应的结构性原因,在中国货币供应机制减小对通货膨胀负向反应和增大对产出正向反应的配合下,政府购买支出和公共投资支出能够对私人消费和私人投资产生正向的挤入效应。