A model of multiple-unit ownership as a diffusion process

This paper develops and tests a new model for multiple-unit adoptions of durable goods based on the diffusion modeling tradition. Multiple-unit adoptions are a major component of sales for many consumer durable product categories. For instance, sales of multiple-unit adoptions for televisions have been higher than both first adoptions and replacement purchases since 1977, while for automobiles, they have represented more than 20% of sales since 1966 in Australia. The structural drivers of multiple-unit adoptions are quite different from either first purchase or replacement purchase. Hence, identifying and modeling the multiple-unit component of sales is important for aggregate sales forecasts. Moreover, consumer requirements for additional units of a product are likely to be considerably different than for the other components of sales (first purchases and replacement purchases). As such, the ratio of the first, multiple, and replacement sales components will strongly influence the product mix requirements of the market.

While forecasting and influencing multiple-unit sales are an important managerial issue, very little attention has been given to multiple-unit ownership in the diffusion modeling literature. The only model available was developed for the purpose of modeling relatively short-term behavior of multiple-unit adoptions, rather than the longer-term pattern of sales. We propose a model of multiple-unit adoptions as a diffusion process.

We apply the model to both color television and automobiles. Analysis of the model's long-term fit and forecasts in these applications provide support for the structure of the new model.     

Does Twitter chatter matter? Online reviews and box office revenues

ABSTRACT

With a rapid rise of text-based social media and online Word-of-Mouth (WOM) activity, millions of people express their thoughts and opinions on a variety of topics. Considering that nowadays WOM is a most influential source of information when guiding consumers’ choice and purchase decisions, in this paper we look at the relationship between Twitter messages (tweets) and cinema box office revenues. Using static and dynamic panel data regression approaches, we show that the frequency, sentiment and timing of tweets posted about a film are correlated to different extent with the movie’s box office revenues, with negative tweets being particularly damaging to the box office revenues. From a managerial perspective, this is important to know, such that film production companies and distributors can adjust their strategy accordingly.     

地方政府住宅用地出让价格跨区域联动模式研究

研究目的:刻画、解构地方政府住宅用地出让价格跨区域联动系统。研究方法:全局向量自回归(GVAR)模型与网络分析工具。研究结果:(1)地方政府住宅用地出让价格跨区域联动系统呈现出高聚类、短路径的"小世界网络"特性。(2)地方政府住宅用地出让价格跨区域联动网络分为3个板块:板块1为"领导人"角色,板块2为"经纪人"角色,板块3为"谄媚人"角色。(3)地方政府住宅用地出让价格跨区域联动表现出明显的空间异质性。研究结论:应该从跨区域联动视角,深化对地方政府住宅用地出让价格形成机制的认识,有效管控地方政府住宅用地出让价格的跨区域影响。     

Social Capital,Income Diversification and Climate Change Adaptation: Panel Data Evidence from Rural Ethiopia

The choice between specialisation and diversification of income is driven by multiple, interacting factors, such as economies of scale and scope, risk considerations, context, and household characteristics. Using panel data from Ethiopia, we investigate the role of social capital and the covariate risk of climate change and their interaction. We find that households with greater social capital tend to be more specialised, implying that diversification and informal insurance are substitutes in the mitigation of risk. We also find that this effect is significantly weaker in regions more prone to climate change, which is consistent with the average farmer being aware that informal insurance is not an effective protection against risks that affect the entire social network. We use instrumental variable random effects estimation to account for the plausible endogeneity of social capital and we also establish that our results do not depend on the poorest and most constrained individuals in our sample.     

茶产业发达地区茶农选择茶叶销售渠道的影响因素分析——基于福建安溪实证

以福建省安溪县茶农问卷调查数据为基础,利用二项Logistic模型对茶农选择茶叶销售渠道的影响因素进行计量分析。研究表明,茶农户主特征的年龄对茶农选择渠道的影响不显著;茶农户主是否是村干部对茶农自家开茶叶店有显著影响;茶农是否参加茶业合作组织对茶农选择茶业合作组织影响显著;茶叶收入占家庭收入的比重0~25%、26%~50%对茶农自家开茶叶店有显著影响,51%~75%对茶农选择茶叶经销商影响显著;农户到最近茶叶交易市场的距离≤3 km,对茶农选择茶叶经销商和茶叶批发市场这2个渠道影响显著。     

Influence of livelihoods on climate change adaptation for smallholder farmers in the Mekong Delta Vietnam

Farmers in the Vietnamese Mekong Delta face a wide range of climate-related and hydrological factors which threaten rice production. Smallholder farmers must adapt to climate change to sustain rice production as their central and most important livelihood activity. A sample was stratified across agro-ecological areas in the Delta affected by flooding, alluvial soils, acid sulphate soils, and saline water intrusion and by derived farmer typologies. A rural livelihoods approach was used in focus group discussions and in-depth interviews to identify and enumerate enabling and constraining adaptation factors. Smallholders experienced diverse natural hazards such as floods, abnormal rains, high temperatures, water scarcity, and salinity intrusion specific to the agro-ecological areas. Adaptation was constrained by labour shortages, water quality, topography, access to combine harvesters, transportation infrastructure, dryers and household savings. Adaptation was enabled by farming techniques and experience, cooperative groups, water quantity, access to information, and ability to purchase agro-chemicals through credit. Small farmers (< 1?ha) were more constrained than large farmers (> 1?ha) who had an expanded livelihood asset base. A range of policy implications are discussed, but adaptation is not just about technological fixes but requires overall improvements in a range of human, social and financial components.     

LearnSmart,adaptive teaching,and student learning effectiveness: An empirical investigation

Facing the growing number of digital natives entering the classroom, business professors look for innovative ways to enhance the student learning experience. The authors focus on the online interactive learning tool LearnSmart (McGraw-Hill, New York, NY), and examine its impact on student learning effectiveness by testing the direct and indirect relationships among perceived competence, perceived challenge, instructors, perceived value, and satisfaction with LearnSmart. Constructionism served as the theoretical foundation for this study. About 215 students at a public university in the United States took the survey and 197 valid responses were received. Regression analysis results showed that the use of LearnSmart improved students' perceived competency, thus increasing their perceived value of using LearnSmart, as well as their satisfaction with LearnSmart. Perceived value was also found to mediate the impact of perceived competency on satisfaction with LearnSmart, and the instructor played a significant role in facilitating and improving student learning. Perceived challenge impacted student's perceived value of using LearnSmart, but it did not influence satisfaction with LearnSmart.     

Pricing a rural development program: uncertainty,indifference, and protest behaviors

This article presents an econometric approach to modeling uncertainty, unwillingness to pay, and protest behavior in contingent valuation studies. For that purpose, a mixture model with sample selection is developed for a multiple‐bounded uncertainty elicitation format. The proposed theoretical framework is applied to evaluate the social welfare impact of implementing a sustainable rural development program. Results show that a “naive” analytical approach that excludes protesters from the analysis would result in significantly higher willingness to pay estimates for those individuals who favor the implementation of the program and agree to reveal their true reservation prices.     

Portfolio optimization based on GARCH-EVT-Copula forecasting models

This study uses GARCH-EVT-copula and ARMA-GARCH-EVT-copula models to perform out-of-sample forecasts and simulate one-day-ahead returns for ten stock indexes. We construct optimal portfolios based on the global minimum variance (GMV), minimum conditional value-at-risk (Min-CVaR) and certainty equivalence tangency (CET) criteria, and model the dependence structure between stock market returns by employing elliptical (Student-$t$ and Gaussian) and Archimedean (Clayton, Frank and Gumbel) copulas. We analyze the performances of 288 risk modeling portfolio strategies using out-of-sample back-testing. Our main finding is that the CET portfolio, based on ARMA-GARCH-EVT-copula forecasts, outperforms the benchmark portfolio based on historical returns. The regression analyses show that GARCH-EVT forecasting models, which use Gaussian or Student-$t$ copulas, are best at reducing the portfolio risk.