Tales from tails: On the empirical distributions of forecasting errors and their implication to risk

When evaluating the performances of time series extrapolation methods, both researchers and practitioners typically focus on the average or median performance according to some specific error metric, such as the absolute error or the absolute percentage error. However, from a risk-assessment point of view, it is far more important to evaluate the distributions of such errors, and especially their tails. For instance, a lack of normality and symmetry in error distributions can have significant implications for decision making, such as in stock control. Moreover, frequently these distributions can only be constructed empirically, as they may be the result of a computationally-intensive non-parametric approach, such as an artificial neural network. This study proposes an approach for evaluating the empirical distributions of forecasting methods and uses it to assess eleven popular time series extrapolation approaches across two different datasets (M3 and ForeDeCk). The results highlight some very interesting tales from the tails.     

美貌能带来幸福感吗?

作为一项稀缺资源，好的外表能够为个体带来多重溢价和福利。文章基于中国家庭追踪调查（CFPS）数据考察了个体的外貌与主观幸福感之间的关系。研究发现，在控制了影响幸福感的其他因素之后，个体的外貌对其幸福感依然有着显著的正向影响：外貌更具吸引力的个体，其自评的生活满意度更高。外貌的这一影响在不同性别、不同年龄段和不同收入群组中均有所差异。同时，在该影响机制中，个体的经济状况扮演着中介渠道的角色。文章运用访员固定效应和工具变量估计控制了模型的内生性问题。     

双元视角下调节聚焦对国防研发人员创新行为的影响机制

调节聚焦作为个体实现目标的动机调节系统，对个体创新行为具有重要作用，是组织行为学领域关注的热点。基于调节聚焦等相关理论，从二维视角深入考察个体调节聚焦对其双元创新的过程机理与边界机制。对527名国防科技研发人员进行问卷调研分析，结果发现：①促进聚焦和防御聚焦均正向预测双元创新及其平衡性与互补性，促进聚焦的预测作用更强；②探索式失败学习和利用式失败学习同时中介上述关系；③正向组织差错管理氛围正向调节促进聚焦与双元创新及其互补性的关系，负向组织差错管理氛围正向调节防御聚焦与双元创新及其互补性的关系。     

Impact of the Fast Track Land Reform Programme (FTLRP) on agricultural production: A tobacco success story in Zimbabwe?

The study ascertained the impact of the Fast Track Land Reform Programme (FTLRP) in Zimbabwe on tobacco production. The Chow Test, Vector Error Correction Model (VECM) and the Vector Error Granger-Causality Test were applied. The results reveal that there was a structural break in tobacco sales in the year 2000. Furthermore, in the long-run, area under tobacco production had a positive impact whilst number of tobacco producers had a negative impact on tobacco sold pre-FTLRP. Post-FTLRP, area of tobacco and number of tobacco producers had negative impact. In addition, the FTLRP induced an 8.94 % increase in the speed of adjustment in correcting the long-run equilibrium in tobacco sales. In the short-run, the FTLRP caused a percentage increase in the area of tobacco production and number of tobacco producers to induce a 0.65 % and 0.76 % increase in the tobacco sales, respectively. Area of tobacco production and number of tobacco producers Granger-caused tobacco sales in the pre-FTLRP period. Post-FTLRP, the number of tobacco growers Granger-caused tobacco sales. It is concluded that the FTLRP had an impact on tobacco sales, mainly through the number of tobacco growers. The study recommends the specialisation and training of the new farmers to improve productivity.     

Are betting returns a useful measure of accuracy in (sports) forecasting?

In an economic context, forecasting models are judged in terms not only of accuracy, but also of profitability. The present paper analyses the counterintuitive relationship between accuracy and profitability in probabilistic (sports) forecasts in relation to betting markets. By making use of theoretical considerations, a simulation model, and real-world datasets from three different sports, we demonstrate the possibility of systematically or randomly generating positive betting returns in the absence of a superior model accuracy. The results have methodological implications for sports forecasting and other domains related to betting markets. Betting returns should not be treated as a valid measure of model accuracy, even though they can be regarded as an adequate measure of profitability. Hence, an improved predictive performance might be achieved by carefully considering the roles of both accuracy and profitability when designing models, or, more specifically, when assessing the in-sample fit of data and evaluating out-of-sample forecasting performances.     

Estimating multimodal public transport mode shares in Athens,Greece

We analyze market shares for each public transport mode in total public transport ridership for the multimodal public transportation system of Athens, Greece. This analysis provides useful information for making investment decisions concerning the public transport infrastructure and for allocating subsidies. Due to the non-stationary properties of the data, cointegration techniques are applied to investigate the long run equilibrium relationships. Error Correction Models are implemented to estimate short run dynamics as well as the speed of adjustment from the short to the long run. Results suggest that fare and GDP are the main determinants of the public transport mode shares both in the short and in the long run. Findings also indicate the role of total ridership fluctuations in explaining variations in public transport mode shares.     

共享型领导对员工建言行为的影响 ——员工权力感的中介作用

本文探讨了共享型领导对员工建言行为的影响,以及员工权力感的中介效应和差错风险承担、角色自我效能感的调节作用,丰富了员工建言行为、共享型领导的相关理论并给出了相应的实践建议。以上海多家企业中的员工以及其直属上级领导作为研究对象,通过194对领导-下属有效调查问卷分析得出了以下结论:①共享型领导对员工的促进性建言与抑制性建言都有显著的正向预测作用;②员工权力感在共享型领导与员工建言行为之间存在中介作用;③差错风险承担在员工权力感与促进性建言之间存在调节作用,角色自我效能感在员工权力感与抑制性建言之间存在调节作用。本文在此研究结果的基础上进行讨论并给出相关管理建议。     

Price transmission,asymmetric adjustment and threshold effects in the cotton supply chain: a case study for Vidarbha,India

This study examines price transmission asymmetries in Vidarbha's (India) cotton supply chain from 2002 to 2012. The analysis takes account of thresholds in price adjustments toward their long‐run equilibrium. The first stage considers the price dynamics between international and Indian domestic cotton prices. The second stage considers price transmission from domestic to farm gate cotton prices in Vidarbha. Results from the first stage indicate that Indian and international cotton markets are well‐integrated. In contrast, the second stage reveals significant threshold‐type nonlinearities as well as asymmetries in price transmission between domestic and farm gate prices. The short‐run dynamics suggest that the pass‐through from domestic to farm gate prices is larger when domestic prices decrease than when they increase. Moreover, back of the envelope calculations suggest that the loss in revenue for a typical farmer from a decrease in domestic price is larger than the gains from an increase in domestic price of the same magnitude. The implication is that traders benefit from price fluctuations at the expense of farmers. Evidence from fieldwork in Vidarbha suggest that asymmetries revealed in this analysis may be linked to trader's market power and inadequate market information among farmers.     

Combining multiple probability predictions using a simple logit model

This paper begins by presenting a simple model of the way in which experts estimate probabilities. The model is then used to construct a likelihood-based aggregation formula for combining multiple probability forecasts. The resulting aggregator has a simple analytical form that depends on a single, easily-interpretable parameter. This makes it computationally simple, attractive for further development, and robust against overfitting. Based on a large-scale dataset in which over 1300 experts tried to predict 69 geopolitical events, our aggregator is found to be superior to several widely-used aggregation algorithms.     

Enhancing adaptive transfer of cross-cultural training: Lessons learned from the broader training literature

Drawing insights from the broader training literature, we argue that evaluation of cross-cultural training effectiveness should adopt comprehensive criteria, including cognitive, skill-based, and affective learning outcomes as well as adaptive transfer. We propose that the integration of an error management supplement in cross-cultural training can enhance trainee acquisition of self-regulation skills and self-efficacy that facilitate adaptive application of learning to novel cultural situations. In addition to the traditional error management training designs (i.e., positive error framing), the current paper describes additional design elements to promote acquisition of cognitive strategies, prevent premature automaticity, alleviate concerns about error occurrence during learning, and enhance readiness to transfer. In addition, we offer propositions regarding the effects of the supplement on learning and transfer outcomes, along with implications for future research and practice on cross-cultural training.