Is silence golden? An inquiry into the meaning of silence in professional product evaluations

The world today is rife with product recommendations from professional critics and experts that are available from numerous sources—television, magazines, radio, internet, etc. Very often these recommendations shape our decisions and choices. In this study, we investigate two main issues regarding expert opinions. First, we present an approach that uses information available from every expert, including those who are silent about the product, to obtain a consensus measure of expert opinion. Our model also allows us to obtain a measure of how informative each expert is and how their information content may vary by type of review. More importantly, our overall measure of expert opinion weights the opinion of each expert based on how informative they are at the particular quality level of the product being evaluated. In other words, we provide consumers with a method that reconciles conflicting expert opinions into a summary measure. The second issue we investigate in this paper is the meaning of “silence” in expert opinions. Our model demonstrates that the fact that an expert is silent about a product may imply a positive or a negative review, depending on the expert. We use data from the motion pictures industry to illustrate our approach. JEL Classification M31     

Logit based parameter estimation in the Rasch model

The similarities between the logistic regression model and the Rasch model (used in psychometric item response theory) are used to derive several methods based on logits that produce parameter estimates for the Rasch model. A result from LeCam and Dzhaparidze is used by which an initial consistent estimate is transformed by one scoring method iteration into an estimate that has the same asymptotic efficiency as the (in this case conditional) maximum likelihood estimate of the item parameters. Indirect evidence about the bias of this CML estimator is produced by studying the (more easily derived) bias of the estimator based on the unweighted logits. Finally, some simple weighted least squares logit-based estimates are presented, and their performance is assessed. On the whole, the computationally simpler logit-based estimates give a fairly good approximation to the CML estimates.     

实验经济学视角下中国家财险需求不足的实证研究

基于心理学注意衰减模型与内驱力降低理论,使用实验经济学处理效应检验和logit回归方法,探究中国家财险需求不足的问题。结果表明：潜在客户家财险决策以接受相关外部刺激为前提,第一阶段先感知家庭财产风险,第二阶段再评估家财险需求;绝大部分潜在客户难以接受到家财险相关外部刺激是导致保险需求不足的重要原因。鉴于此,可从转变财产险公司营销方式与经营理念、充分履行房地产与物业管理公司自身服务义务、有效发挥政府社会管理职能这三方面着手,将潜在需求逐步转化为家财险保单。     

Consumer willingness to pay for traditional food products

Reflecting the growing interest from both consumers and policymakers, and building on recent developments in Willingness to Pay (WTP) methodologies, we evaluate consumer preferences for an archetypal traditional food product. Specifically we draw on stated preference data from a discrete choice experiment, considering the traditional Hungarian mangalitza salami. A WTP space specification of the generalized multinomial logit model is employed, which accounts for not only heterogeneity in preferences but also differences in the scale of the idiosyncratic error term. Results indicate that traditional food products can command a substantial premium, albeit contingent on effective quality certification, authentic product composition and effective choice of retail outlet. Promising consumer segments and policy implications are identified.     

Quality certification vs. product traceability: Consumer preferences for informational attributes of pork in Georgia

Consumer willingness-to-pay for informational attributes of food products is important information for food producers and supply chain participants and policy makers. We examine consumer demand in the pork sector of the Republic of Georgia. Results of conditional and mixed logit estimation, conducted on choice experiment data, reveal that Georgian consumers treat quality certification and product traceability attributes as substitutes. We also find that producers and other supply chain participants should be concerned primarily with maintaining the appearance of pork products. Retailer specific factors such as location and type of outlet can also substitute for product traceability. Store location and product appearance, however, are complementary attributes. In light of the recent turbulence in Georgia these consideration may be of paramount importance as participants in the supply chain seek to rebuild damaged infrastructure.     

Sustainable intensification among smallholder maize farmers in Ethiopia: Adoption and impacts under rainfall and unobserved heterogeneity

In addition to experimental data, using information collected from farmers is vital to assess the performance of candidate farming technologies. The latter provides the basis for farmers’ assessments and adoption decisions. Using detailed georeferenced plot and household level data from Ethiopia, this paper estimates the impact of a set of sustainability-enhancing agronomic practices on maize yields and implied net maize income with the aid of multinomial endogenous regime-switching regression that corrects for unobserved heterogeneity. The treatments’ effects on yield ranged from 29.5% for the fertilizer-dominant strategy to 88% in the case of fertilizer, maize-legume diversification, and soil and water conservation combinations. Second, while the impacts of the agronomic packages are significant in almost all states of the world, there were considerable heterogeneity effects conditioned on observed rainfall deviations from the historical average with levels effects of up to 92% and heterogeneity effects of 33–64%. The heterogeneous and rainfall-conditioned impacts point to the role of local biophysical modifiers of the impacts of agricultural practices. Investments in context-appropriate adaptation in agricultural research and extension is suggested.     

中小板上市公司管理层盈余预测质量的影响因素研究

管理层盈余预测是中小板上市公司对未来展望的信息,在信息披露中占据着越来越重要的地位。本文选取2013-2015 年中小板上市公司相关数据,运用广义多分类无序logit 模型对影响中小板上市公司管理层盈余预测质量的因素进行探究,以期提高管理层盈余预测的质量。经研究结果表明,公司的独立董事占比、年度召开董事会次数、股权集中度、净资产收益率、管理层持股比例等因素越高,对提高中小板上市公司管理层盈余预测质量越有益,除此之外,中小板上市公司董事长和总经理兼任情况,与公司合作的审计机构专业程度均对管理层盈余预测的质量有一定影响。     

Soil texture prediction via reduced K-means Principal Component Multinomial Regression

Texture is one of the most important physical property of the soils for its influence on other fundamental properties. It is defined according to particle size distribution, that can be accurately measured in laboratory. However, these measurements are costly and very time consuming, therefore valid alternatives are necessary. In last years some statistical techniques have been used to predict textural classification using values of reflectance spectrometry as explicative variables. The estimation of the model parameters can be not too accurate, affecting prediction when there is multicollinearity among predictors. Another issue can be the great number of explicative variables usually necessary to explain the response. In order to improve the accuracy of the prediction in classification problems under multicollinearity and to reduce the dimension of the problem with continuous covariates, in this paper we introduce a new technique, based on classification and dimension reduction methods. We show how the new proposal can improve the accuracy of prediction, considering a problem concerning the textural classification of soils of Campania region.     

Remittances and household expenditure behaviour: Evidence from Senegal1

We use different econometric techniques, from propensity score matching to multinomial treatment methods, to assess the impact of internal and external remittances on several household budget shares in Senegal. When only considering the average impact of remittances on the household expenditure behaviour, we find an overall productive use of remittances. However, the impact of remittances disappears when the marginal spending behaviour is considered, i.e., households do not show a different consumption pattern with respect to their remittance status. The marginal spending behaviour therefore suggests that, in the decision on how to allocate expenditure, remittances are treated just as any other source of income.     

利率市场化背景下信用风险的测度及影响

随着利率市场化程度的不断提高,逐步增大的利率波动必然对上市公司的信用风险产生一定影响。本文首先采用Logit模型对2006年第四季度至2013年第四季度228家上市公司的信用风险进行度量,预测出上市公司违约概率;其次选用Shibor数据求出各季度的利率波动率;最后选用宏观经济因素及利率波动率为自变量,信用风险为因变量建立风险测度模型,结果表明利率波动对信用风险有负相关关系,即随着利率市场化进程的加快,企业的信用风险有降低的趋势,因此可考虑加快利率市场化改革的步伐。