Testing hypothetical bias in a framed field experiment

Hypothetical bias is tested based on inter- and intra-respondent comparisons of choice behavior, applying a hypothetical and real choice experiment. The inter-respondent comparison commonly applied in the environmental and agricultural economics literature consists of a control group of buyers who are asked to hypothetically choose between conventional and organic beans and an experimental group of buyers who are endowed to purchase the same beans using an identical experimental design. Hypothetical bias is tested by comparing inter- and intra-respondents’ (i) hypothetical and real choices, (ii) preference parameters of the estimated choice models related to hypothetical and real choices, and (iii) hypothetical and real willingness to pay (WTP). Choices in the experimental group are highly consistent when switching from hypothetical to real choices for this study's homegrown goods. However, after being endowed, the price sensitivity of lower income households drops, suggesting a house money effect. WTP derived from actual purchases is higher than WTP based on hypothetical choices, indicating a negative hypothetical bias, but differences are only significant in the case of the inter-respondent comparison. Actual prices paid by respondents in the field experiment appear to be considerably lower than the estimated WTP values and yield a mixed picture of hypothetical bias.     

US–China rivalry: The macro policy choices

Stylised representations of recent US and Chinese tax reforms, tariffs against imports and alternative Chinese monetary targeting are examined using a calibrated global macro model that embodies both trade and financial interdependencies. For both countries, unilateral capital tax relief and bilateral tariffs are shown to be ‘beggar thy neighbor’ policies. As large economies, both enjoy ‘optimal tariffs’, even bilaterally, though net outcomes are shown to depend on the allocation of revenues. Bilateral tariffs are most advantageous for the US if the additional revenue finances indirect tax relief. Once US bilateral tariffs are imposed, China is a net loser irrespective of its policy response, though a currency float is shown to cushion the effects on its GDP in the short run. Equilibria in normal form non-cooperative tariff games have the US imposing tariffs while China liberalises.     

基于ProCAST数值模拟的高铬钢复合轧辊结合层夹渣成因分析

为解决高铬钢复合轧辊离心复合铸造生产中的结合层夹渣问题,以复合铸造过程数值模拟与夹渣物XRD分析相结合,分析了该夹渣成分及分布原因。首先,通过宏观检查并利用XRD实验定性分析了夹渣物的组成,初步确定了夹渣物为生产中高温反应生成的非金属夹渣,且集中分布于辊身冒口端。其次,采用数值模拟的方法分析了高铬钢轧辊复合铸造的生产过程,对比研究了离心铸造和重力铸造2个阶段辊身冒口端与底端的高温金属流动与温度场演变差异。模拟结果表明:芯部重力铸造时,芯部高温金属液对轧辊外层冲刷作用的差异是夹渣物主要分布于辊身冒口端的重要原因。通过复合铸造过程流场与温度场的模拟结果,对高铬钢复合轧辊结合层夹渣物的产生和分布原因进行分析,对于改善离心铸造轧辊缺陷的产生具有借鉴意义。     

局部反循环打捞装置数值模拟

为了明确常规局部反循环洗井装置在井下形成反循环的机理及其目前洗井效果不理想的原因,解决其在应用过程中碎屑提取率低的问题,采用计算流体力学方法,建立该装置洗井作业时的孔底固液两相流场计算模型,分析液相洗井介质在冲洗碎屑过程中的压力场、速度场分布及湍流特征。模拟计算得出:液相洗井介质的压力、流速及湍动能耗散主要发生在进入孔底流场前的两次出水孔换向过程中,导致其对孔底中部的碎屑冲洗能力不足,部分碎屑滞留在孔底中部。为改善反循环洗井装置的洗井效果,可改进下出水孔的结构,将下出水孔位置适当下移或缩小下出水孔直径,通过增大孔底处洗井介质流速来提升其对碎屑的携带能力。研究结果可为局部反循环打捞装置的优化设计提供参考。     

缝洞型油藏溶洞内水驱流态研究

为研究缝洞型油藏溶洞中注水速度和黏度对水驱波及面积和油水界面的影响,利用Fluent数值模拟软件从流体力学角度对单缝洞油藏溶洞内流体流动进行了数值模拟,采用VOF模型对油水两项界面进行跟踪。研究发现,入口水速一定时,波及面积随着黏度的增大逐渐增大,油水界面呈对称均匀推进,黏度较小的原油水相会趋向中心线向洞口流动并产生漩涡,随着黏度逐渐增大,漩涡逐渐消失,驱替方式逐渐转变成活塞式驱替;原油黏度一定时,波及面积随着入口速度的增加而减小,油水界面呈对称趋势均匀推进,水速较大时水相会趋向中心线向洞口流动并有漩涡产生,随着入口水速增大,趋势逐渐明显。研究结果可为进一步完善缝洞型油藏溶洞内水驱过程中油水两相的流态分析提供参考。     

A discrete-choice experiment to assess treatment modality preferences of patients with anxiety disorder

Aims: The aim of this study was to elicit the preference of patients with an anxiety disorder regarding treatment modalities. Understanding patients’ preferences could help optimize treatment uptake and adherence to therapeutic interventions.

Materials and methods: A discrete-choice experiment was used to elicit patients’ preferences with regard to four treatment characteristics: waiting time until first treatment, intensity of treatment, face-to-face vs digital treatment, and group size. In 12 choice sets, participants were asked to choose between two treatment alternatives. A random parameters logit model was used to analyse the data.

Results: A total of 126 participants, aged 18?years and older, currently or in the previous year in treatment for an anxiety disorder, completed the survey. Respondents preferred short (over long) waiting times, face-to-face (over digital) treatment, individual (over group) treatment and a treatment intensity of one session per week rather than two sessions per week or one session every two weeks. Waiting time and treatment intensity were substantially less important to patients than level of digitalization and group size. Heterogeneity in preference was significant for each attribute, and sub-group analyses revealed this was partly related to education level and age.

Limitations: The convenience sample over-represented the female and younger population, limiting generalizability. Limited information on background characteristics limited the possibilities to explore preference heterogeneity.

Conclusions: This study demonstrated how different treatment components for anxiety disorders affect patients’ preferences for those treatments. There is significant variation in treatment preferences, even after accounting for age and education. Incorporating patients’ preferences into treatment decisions could potentially lead to improved adherence of treatments for anxiety disorders.     

The influence of group size on distributional fairness under voting by veto

Voting by Veto [VBV], developed by Dennis C. Mueller, is a two-stage voting mechanism for committee decision making. In the first stage, every member of the committee makes a proposal. The proposals are joined with the current status quo (or another fallback option). For the second stage, a random mechanism determines the order of voting and the committee members sequentially eliminate one alternative each. After every committee member has exercised her veto, a single winning alternative remains. Game theory predicts that the equality of the resulting distribution under VBV varies with group size. Hence, decisions in two-member groups should result in highly unequal distributions of benefits. With increasing group size, however, VBV should generate more equally distributed outcomes. We examine the effect of group size under VBV in a series of laboratory experiments where groups with a varying number of members play a ‘divide the dollar game’. Our results confirm that larger groups choose more equal distributions than smaller groups. However, we also find deviations from the model's predictions. Some committees in our experiment do not select Pareto-optimal alternatives. An exploratory analysis of possible explanations suggests that individual behavior is most likely motivated by a combination of material self-interest and social preferences such as reciprocity and fairness.     

Book belly band as a visual cue: Assessing its impact on consumers’ in-store responses

This research investigates the role of a widely used, yet under-investigated packaging cue: the paper strip that wraps around books, known as the belly band. Drawing on cue utilization theory, we conducted a pilot study, a laboratory experiment and a field study in two real-life bookshops to analyze the effects of belly bands on consumers' responses, as well as on actual browsing and purchasing behavior. The results suggest that the belly band acts primarily as a visual cue; has a significant effect on actual browsing and purchasing behavior; and stimulates unplanned behaviors, producing a carryover effect on the assortment even if it does not alter the customer's budget.     

Design Factors Influencing Willingness‐to‐Pay Estimates in the Becker‐DeGroot‐Marschak (BDM) Mechanism and the Non‐hypothetical Choice Experiment: A Case of Biofortified Maize in Zambia

Two of the experimental methods used to estimate willingness‐to‐pay (WTP) for a non‐market good, the Becker‐DeGroot‐Marschak (BDM) mechanism and the non‐hypothetical choice experiment (nHCE) often lead to significantly different WTP estimates, complicating the choice between the methods. In Zambia the same group of researchers used both techniques to evaluate WTP for orange maize, which provides more vitamin A than other varieties. This provided an opportunity to analyse the sources of the difference. In the BDM experiment, one group of respondents was provided with more training opportunities than the other, and made higher bids. Accounting for lexicographic behaviour in the nHCE reduced the estimated WTP. These two design factors together resulted in a decrease in the WTP difference for orange maize (1,279–632 ZMK) although the difference remains statistically significant. More training was also shown to eliminate the effects of different orders in which maize varieties were presented.     

The Use of Conditional Cost Functions to Generate Estimable Mixed Demand Systems

Mixed demand systems have been virtually ignored in empirical work solely because derivation of these systems requires closed forms for both direct and indirect utility functions. This article proposes the alternative of using a conditional cost function to generate empirical mixed demand models. This approach allows the estimation of mixed demand systems, which are explicit in an unobservable variable (utility), but may lack a closed form representation in terms of observable variables such as prices, quantities and expenditure. Results indicate that this approach is operationally feasible, which opens up a wider range of mixed demand specifications in static analyses.