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.     

Modeling asymmetric price transmission in the European food market

In this study, we employ a multivariate panel error correction model (PVECM) to investigate asymmetric price transmission among the farm, processor, and retail segments of the European food supply chain for the 2005–2016 period. The results indicate that, in both the long- and short-run, retail prices respond more strongly to processor price increases than decreases and the same occurs for processor prices due to farm price changes. Thus, the findings demonstrate the presence of positive asymmetric price transmission in the European food supply chain. Finally, the results of the present study indicate that the food price pass-through varies greatly across product category and across countries, and that the pass-through to producer prices is greater than that to consumer prices.     

Climate,diseases, and the origins of corruption

It has been commonly observed that tropical countries tend to suffer from intense corruption and underdevelopment. This study provides an explanation for this long-standing disparity across the world based on variation in the intensity of ultraviolet radiation (UV-R). The central hypothesis is that UV-R is positively associated with the (historical) prevalence of eye diseases, which significantly shortens work-life expectancy as a skilled worker. This helps shape the worldwide distribution of corruption by affecting the incumbents' window of opportunity. Using data for up to 139 countries, I consistently find empirical support for the positive relationship between UV-R and corruption. The main findings withstand accounting for numerous alternative explanations for international differences in corruption levels. Employing individual-level data from the World Values Survey, I document suggestive evidence that exposure to UV-R is linked to surveyed respondents' tolerance towards corrupt activities. Furthermore, a subnational analysis for China lends credence to the cross-country evidence.     

Forecasting the Covid-19 recession and recovery: Lessons from the financial crisis

We consider simple methods to improve the growth nowcasts and forecasts obtained by mixed-frequency MIDAS and UMIDAS models with a variety of indicators during the Covid-19 crisis and recovery period, such as combining forecasts across various specifications for the same model and/or across different models, extending the model specification by adding MA terms, enhancing the estimation method by taking a similarity approach, and adjusting the forecasts to put them back on track using a specific form of intercept correction. Among these methods, adjusting the original nowcasts and forecasts by an amount similar to the nowcast and forecast errors made during the financial crisis and subsequent recovery seems to produce the best results for the US, notwithstanding the different source and characteristics of the financial crisis. In particular, the adjusted growth nowcasts for 2020Q1 get closer to the actual value, and the adjusted forecasts based on alternative indicators become much more similar, all unfortunately indicating a much slower recovery than without adjustment, and very persistent negative effects on trend growth. Similar findings also emerge for forecasts by institutions, for survey forecasts, and for the other G7 countries.     

中国城市公园的标度律特征分析

科学研判城市公园面积与人口规模的关系,有利于 客观认识和指导城市的可持续发展。采用1996—2019年中 国291个地级及以上城市公园面积与人口规模数据,探究二者 之间的标度关系及其标度因子的时空演化规律,进而采用基于 标度律的公园规模修正模型度量各城市公园面积达到预期值的 程度,并对规模修正指标和人均公园面积进行比较分析,得到 如下结果。1)我国公园面积与人口规模整体呈亚线性规模缩 放关系,公园具有显著规模效应,符合城市标度律特征;时间 上呈现亚线性-超线性-亚线性的阶段性波动演变特征,空间 上分异明显：华南接近线性标度关系,华中、东北、华北、西 南呈典型亚线性关系,华东、西北呈亚线性,但标度因子偏离 度较大。2)大城市在人均公园面积排序中相对靠后,在考虑 规模效应后,排名普遍提高,说明规模修正指标能在消除人口 规模影响的基础上,有效衡量不同规模城市公园面积的水平。 标度律视角下的城市公园规模测度能够为城市人口管理和公园 面积发展的决策提供科学指导,为不同规模城市公园建设提供 可借鉴的比较标准,促进公园与人口的协调发展。     

优化外商直接投资结构的研究——基于行业FDI数据的VAR模型

根据1990—2010年全国国内生产总值（GDP）、FDI在制造业的投资额（FM）、FDI在服务业的投资额（FS）、FDI在房地产业的投资额（FRE）及在教育领域的投资额（FE）的统计数据进行基于VAR模型的实证分析,认为长期看,外商在制造业的投资额（FM）和在服务业的投资额（FS）的增加导致全国GDP的增加,外商在房地产业的投资额（FRE）以及在教育领域的投资额（FE）与GDP反向变动;短期看,对全国经济发展的短期影响程度由高到低,依次是FDI在服务业的投资额（FS）、在制造业的投资额（FM）和在教育领域的投资额（FE）以及在房地产业的投资额（FRE）。建议以国务院颁布的《外商投资产业指导目录》为导向,积极利用外资及优化外商投资结构,在发挥外资对我国经济的积极推动作用的同时尽量减少外资的负面影响。     

浅谈涵洞浆砌工程质量纠正控制措施

近年浆砌工程在重大高速公路应用及其广泛,但施工结束还未交工验收时就出现脱落、裂缝等问题。针对此问题我合同段积极采取实质、外观质量纠正和控制措施,以供大家参考和相互学习。     

Nonlinearity and time-variation in the monetary model of exchange rates

In this paper we analyze the existence of nonlinear relationships between macroeconomic fundamentals and exchange rates for some major industrialized countries using an error correction model with time-varying parameters for the post Bretton Woods period. We find that inflation rate differentials with respect to the US inflation rate are the driving forces for the nonlinear relationships in the monetary model for exchange rates for the data from Germany, the UK, Canada, France and Italy. In addition to the variables in the traditional monetary model, also the relative interest rates are relevant in determining exchange rate changes only when the inflation differentials are either very large or very small. In contrast to previous studies we find significant long-run effects in the error correction representation of the monetary model for exchange rates when the nonlinear dynamics is taken into account in the analysis.     

Asymptotically unbiased estimation of autocovariances and autocorrelations for panel data with incidental trends

We consider the estimation of autocovariances using panel data with incidental trends under double asymptotics. The conventional autocovariance estimator suffers from a bias whose value is approximated by twice the long-run variance. We propose a bias-corrected estimator.     

皖江城市带城市经济联系与中心城市辐射范围分析

分析经济区内城市间经济联系不仅有利于引导城市的空间发展,而且有利于空间经济的合理组织。以皖江城市带为例,引入克鲁格曼指数、建成区面积、人口素质权重系数等指标修正了以往的引力模型,并利用城市间的日发车班次数据对修正模型进行了检验。在此基础上,利用修正模型确定了各城市的主要对外联系方向及联系强度,采用断裂点公式计算了中心城市的吸引范围。结果表明:①皖江城市带内各城市对外经济联系强度差异较大;②各城市的主要联系方向呈现中心城市指向性和地域相邻指向性特征;③合肥和芜湖为皖江城市带的两个经济中心城市,它们的对外吸引范围较为狭小。