Forecasting economic time series using flexible versus fixed specification and linear versus nonlinear econometric models

Nine macroeconomic variables are forecast in a real-time scenario using a variety of flexible specification, fixed specification, linear, and nonlinear econometric models. All models are allowed to evolve through time, and our analysis focuses on model selection and performance. In the context of real-time forecasts, flexible specification models (including linear autoregressive models with exogenous variables and nonlinear artificial neural networks) appear to offer a useful and viable alternative to less flexible fixed specification linear models for a subset of the economic variables which we examine, particularly at forecast horizons greater than 1-step ahead. We speculate that one reason for this result is that the economy is evolving (rather slowly) over time. This feature cannot easily be captured by fixed specification linear models, however, and manifests itself in the form of evolving coefficient estimates. We also provide additional evidence supporting the claim that models which ‘win’ based on one model selection criterion (say a squared error measure) do not necessarily win when an alternative selection criterion is used (say a confusion rate measure), thus highlighting the importance of the particular cost function which is used by forecasters and ‘end-users’ to evaluate their models. A wide variety of different model selection criteria and statistical tests are used to illustrate our findings.     

银行风险偏好对企业发展影响的实证研究

从行业层面和企业层面实证研究了银行信贷选择对行业和企业发展的影响。结果发现:在行业层面,银行偏好于固定资产比率较高的行业,因此在信贷资源较为紧张的地区,固定资产比率较高的行业会发展得较好,可见长期内银行选择会影响一个地区的产业结构;在公司层面,银行偏好于行业中固定资产比率较高的企业,而企业为了获得信贷资源也会调整其发展策略,倾向于积累固定资产。指出:中国应该大力发展非银行融资渠道,减弱金融系统对经济发展的扭曲。     

The politics of redistributive social insurance

This paper analyses the political support for a social insurance that includes elements of redistribution when there exists an imperfect private insurance alternative. Individuals differ both in their income and risk. The social insurance is compulsory and charges an income-related contribution with pooling of risks. The private insurance is voluntary and charges a contribution based on individual risks. However due to the adverse selection problem, private insurance companies provide only partial insurance. Adopting a non-expected utility model, we show that there is a general majority support for social insurance and that this support is increasing with risk aversion. We also show that a mixed insurance is politically impossible, regardless of the degree of redistribution of social insurance and the joint distribution of risk and income in the population. Lastly, we analyse how the political support for social insurance is affected by any change in its redistributive component and the possibility of using genetic tests.     

创业企业IPO靠自己还是靠"风投"?——基于双边选择效应视角的经验证据

风险投资的增值职能对创业企业至关重要,是风险投资领域最重要的研究问题之一.现有文献侧重于风险投资增值职能与单边选择效应的分离识别.文章提出双边选择效应与风险投资增值职能的区分,研究了风险投资增值职能对企业IPO结果的作用机制.文章利用1999-2009年风险投资机构投资中国创业企业的1 623个样本,以及截至2016年6月30日被投资企业IPO成功与否的数据,考察了风险投资机构是否发挥了增值职能.文章在充分考虑"好风投"与"好企业"更容易结合的双边选择效应基础上,同时考察了风险投资机构和创业企业自身在IPO过程中可能存在的"增值效应".实证分析和稳健性检验均表明,"好风投"未能充分发挥对创业企业的增值效应,在推动IPO方面的影响并不显著,而创业企业的自身优势才是其更容易成功IPO的主要决定因素.文章的研究为理解风险投资机构的增值职能提供了新的视角,有助于正确认识风险投资机构和创业企业的行为特征及其经济效率.     

Estimating gravity equation models in the presence of sample selection and heteroscedasticity

Gravity models are widely used to explain patterns of trade. However, two stylized features of trade data, sample selection and heteroscedasticity challenge the estimation of gravity models. We propose a two-step method of moments (TS-MM) estimator that deals with both issues. The Monte-Carlo experiments show that the TS-MM estimates are resistant to various combinations of sample selection and heteroscedasticity. Moreover, the TS-MM estimator performs reasonably well even when the data generating process deviates from the TS-MM assumptions. We revisit the world trade in 1990 to illustrate the usefulness of the proposed model, with emphasis on the identification of the extensive margin of trade.     

Are house prices in South Africa really nonstationary? Evidence from SPSM-based panel KSS test with a Fourier function

This study applies the sequential panel selection method (SPSM) to investigate the time-series properties of provincial house prices for entire, large, medium and small middle-segments of South Africa. Quarterly time-series data were collected from nine provinces in South Africa for different house-size categories over the period of 1978.Q1 to 2012.Q4. Whereas other panel-based unit-root tests are joint tests of a unit root for all members of a panel and are incapable of determining the mix of integrated of order zero (I(0)) series and integrated of order one (I(1)) series in a panel setting, the SPSM proposed by Chortareas and Kapetanios (2009) can clearly identify how many and which series in the panel are stationary processes by classifying a whole panel into a group of stationary and nonstationary series. The empirical results from several panel-based, as well as standard pure time-series, unit-root tests, indicate that house prices for the nine provinces studied here are either stationary or nonstationary. However, results from the SPSM using the panel version of the Kapetanios et al. (KSS, 2003) test with a Fourier function unequivocally indicate that house prices are stationary for the nine provinces under study. Our test results have important economic and policy implications for South Africa.     

Trade,labour market rigidity,and aggregate productivity in OECD countries

As the economy becomes more open to trade, aggregate productivity can increase by driving out the least productive firms (the selection effect). Since the selection effect reallocates resources toward the more productive firms, this process can be hindered by rigidity in domestic labour market institutions. Based on the selection effect by Melitz (2003), this article empirically examines how rigidity in labour market institutions affects the consequence of trade on aggregate productivity. Findings from panel dynamic ordinary least square (DOLS) estimators suggest that a high degree of labour market rigidity in an open economy reduces Total Factor Productivity (TFP). In particular, in the case of extremely high labour market rigidity but low foreign R&D capital stocks, openness to trade can cause a country to experience decreasing TFP.     

Productivity and R&D sources: evidence for Catalan firms

This paper draws on a sample of innovative Catalan firms to identify how two main sources of innovation – internal R&D and external R&D acquisition – affect productivity in the manufacturing and service industries. The sample comprises 1612 innovative firms from the fourth European Community Innovation Survey (CIS-4) during the period 2002–2004. We compare empirical results when applying the usual OLS and quantile regression techniques controlling with a non-parametric sample selection. Our results indicate the different patterns that are attributable to the two sources of innovation as we move up from lower to higher conditional quantiles. First, the marginal effect of internal R&D on productivity decreased as we moved up to higher productivity levels. Second, the marginal effect of external R&D acquisition increased as we moved up to higher productivity levels. Finally, empirical results show significant complementarities between internal and external R&D, which are higher for knowledge-intensive service sectors.     

Implementing technology roadmapping with supplier selection for semiconductor manufacturing companies

The rapid pace of technological innovation in the semiconductor manufacturing industry has necessitated the acquisition of competitive advantage from strategic technology planning. The vital requisite for this is well-timed investment including the replacement of old equipment with advanced new equipment. In such investment, selecting the appropriate semiconductor manufacturing equipment from the appropriate supplier is a key factor for successful technology planning. Therefore, equipment supplier selection should be taken into account in the technology planning of semiconductor manufacturing companies. One of the most widely used tools for technology planning is the technology roadmap (TRM). However, conventional TRMs have not considered the task of supplier selection. To address this limitation, this study proposes an extended, four-layered TRM that adds the layer of equipment supplier to the conventional layers of market, product, and technology. The equipment suppliers to be included in the new layer are selected from the supplier portfolio matrix composed of two performance axes: supplier performance and equipment performance. The candidates of equipment suppliers are placed on the supplier portfolio matrix according to the values of two axes determined by evaluation using the analytic hierarchy process (AHP). The proposed TRM is expected to be useful for technology planning by adding a consideration for equipment supplier selection in semiconductor manufacturing companies.     

On the Endogeneity of the Mean-Variance Efficient Frontier

The endogeneity of the efficient frontier in the mean-variance model of portfolio selection is commonly obscured in the portfolio selection literature and in widely used textbooks. The authors demonstrate this endogeneity and discuss the impact of parameter changes on the mean-variance efficient frontier and on the beta coefficients of individual assets.