An in-sample and out-of-sample empirical investigation of the nonlinearity in house prices of South Africa

This paper tests whether housing prices in the five segments of the South African housing market, namely large-middle, medium-middle, small-middle, luxury and affordable, exhibit non-linearity based on smooth transition autoregressive (STAR) models estimated using quarterly data from 1970:Q2 to 2009:Q3. Findings point to an overwhelming evidence of non-linearity in these five segments based on in-sample evaluation of the linear and non-linear models. We next provide further support for non-linearity by comparing one- to four-quarters-ahead out-of-sample forecasts of the non-linear time series model with those of the classical and Bayesian versions of the linear autoregressive (AR) models for each of these segments, for the out-of-sample horizon 2001:Q1 to 2009:Q3, using the in-sample period 1970:Q2 to 2000:Q4. Our results indicate that barring the one-, two and four-step(s)-ahead forecasts of the small segment, the non-linear model always outperforms the linear models. In addition, given the existence of strong causal relationship amongst the house prices of the five segments, the multivariate versions of the linear (classical and Bayesian) and STAR (MSTAR) models were also estimated. The MSTAR always outperformed the best performing univariate and multivariate linear models. Thus, our results highlight the importance of accounting for non-linearity, as well as the possible interrelationship amongst the variables under consideration, especially for forecasting.     

FOOD INSECURITY AND INSUFFICIENCY AT LOW LEVELS OF FOOD EXPENDITURES

In this study we investigate the external validity of the food insecurity and insufficiency measures—specifically, how these measures correlate with food expenditures—using the December 2003 Food Security Supplement of the Current Population Survey. We focus on a special segment of the population—households with low incomes and low food expenditures. If reports of food problems are based on a lack of food, reports should be nearly ubiquitous at the bottom of the expenditure distribution. We find, however, that this is not the case. We define and scale food expenditures several different ways and find that the reported incidence of food insecurity never rises above one‐half anywhere along the corresponding expenditure distributions, leading to concerns about the external validity of the measure.     

我国“十二五”发展的条件、环境和任务

＂十二五＂是基于建国60周年经济社会发展基础上新的建设时期,也是在国际金融危机后中国将要实行的第一个五年规划,本文在分析我国现阶段经济社会发展初始条件基础上,从内部环境、国际环境、体制环境等视角研究了金融危机后我国面临的国内外经济变量,指出了＂十二五＂期间我国经济发展面临的机遇,最后提出了我国经济发展的任务。     

“十二五”时期中部传统农业大省外围区与中心区经济协调发展研究

文章提出了在保障国家粮食安全、不牺牲中心区发展速度等约束条件下,促进中部传统农业大省外围区与中心区经济协调发展的总体方案,即加快外围区农村综合改革,培育与壮大外围区区域性中心城市,推进省级边界区域的开放与合作。在这一方案的贯彻实施中,应当注重农民专业合作组织的建设,强化外围区中心城市的产业支撑作用,推动边界区域一体化合作组织的成立。     

深入社会改革,加快建设和谐无锡——无锡“十二五”社会改革途径探讨

经过三十多年的改革开放以后,无锡和全国一样,经济社会有了巨大的发展,但是,社会发展滞后于经济发展的情况仍然存在,急需深入社会改革,推动社会发展。本文在回顾无锡在"十一五"期间社会改革取得的成就基础上,分析了无锡社会发展存在的问题和面临的挑战和机遇,提出了"十二五"期间无锡深化社会改革的目标以及在政府职能转换、社会管理模式创新、实现公共服务均等化和城乡协调发展等四个方面的改革建议,最后提出了保障改革的一些措施。     

Interlocked Village Markets and Trader Idiosyncrasy in Rural India

The role of traders and traditional exchange institutions has received little attention in empirical research on rural markets in developing countries. We use detailed data on transactions in a village commodity market in India and identify two observed anomalies: first, the repeal of the law of one price, and second, a trader‐idiosyncratic effect, namely that large volumes are sold to a trader who does not offer the best price. Econometric analysis demonstrates that trader idiosyncrasy can largely be explained by reciprocity motives in interlocked village markets. Reciprocity leads to market inefficiencies and can result in unexpected supply responses.     

Estimating consumer willingness to pay for food quality with experimental auctions: the case of yellow versus fortified maize meal in Kenya

Biofortification of maize with provitamin A carotenoids is a new approach to the alleviation of vitamin A deficiencies in Africa. Unfortunately these varieties are yellow or orange, while consumers generally prefer white. Consumer willingness to pay for yellow and fortified maize was compared in experimental auctions in three regions in Kenya. The premium that consumers are willing pay for fortified maize (24%) was higher than the discount they require to buy yellow maize (11%), and in one zone consumers prefer yellow. Yellow color is, therefore, not an impossible obstacle for biofortified maize, although it would clearly be easier to introduce this maize first in regions where yellow maize is currently grown.     

Consumer demand for nutrition versus taste in four major food categories

This study addresses the trade‐off between nutrition and taste in expenditure on breakfast cereal, milk, bread, and soft drinks. Within each category, products have similar cost and convenience, but have markedly different flavor and nutritional content. Using annual expenditure data for a large sample of households participating in the ACNielsen Homescan system, we regress a measure of “healthiness” on household demographics and market prices, and find that households with college‐educated heads and higher incomes made significantly healthier choices in all four categories. These effects are puzzling in that the nutritional differences between products were well known to consumers, and there are no cost or convenience differences between them. The presence of children was associated with less healthy choices, especially for cereal and bread, while older households made healthier choices in all categories except milk.