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Research Collection School Of Economics

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2018

Articles 31 - 60 of 79

Full-Text Articles in Social and Behavioral Sciences

Aging Suppresses Skin-Derived Circulating Sdf1 To Promote Full-Thickness Tissue Regeneration, Mailyn A. Nishiguchi, Casey A. Spencer, Denis H. Y. Leung, Thomas H. Leung Sep 2018

Aging Suppresses Skin-Derived Circulating Sdf1 To Promote Full-Thickness Tissue Regeneration, Mailyn A. Nishiguchi, Casey A. Spencer, Denis H. Y. Leung, Thomas H. Leung

Research Collection School Of Economics

Physicians have observed that surgical wounds in the elderly heal with thinner scars than wounds in young patients. Understanding this phenomenon may reveal strategies for promoting scarless wound repair. We show that full-thickness skin wounds in aged but not young mice fully regenerate. Exposure of aged animals to blood from young mice by parabiosis counteracts this regenerative capacity. The secreted factor, stromal-derived factor 1 (SDF1), is expressed at higher levels in wounded skin of young mice. Genetic deletion of SDF1 in young skin enhanced tissue regeneration. In aged mice, enhancer of zeste homolog 2 (EZH2) and histone H3 lysine 27 …

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Homogeneity Pursuit In Panel Data Models: Theory And Application, Wuyi Wang, Peter C. B. Phillips, Liangjun Su Sep 2018

Homogeneity Pursuit In Panel Data Models: Theory And Application, Wuyi Wang, Peter C. B. Phillips, Liangjun Su

Research Collection School Of Economics

This paper studies the estimation of a panel data model with latent structures where individuals can be classified into different groups with the slope parameters being homogeneous within the same group but heterogeneous across groups. To identify the unknown group structure of vector parameters, we design an algorithm called Panel-CARDS. We show that it can identify the true group structure asymptotically and estimate the model parameters consistently at the same time. Simulations evaluate the performance and corroborate the asymptotic theory in several practical design settings. The empirical application reveals the heterogeneous grouping effect of income on democracy.

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Innovation, Firm Size Distribution, And Gains From Trade, Yi-Fan Chen, Wen-Tai Hsu, Shin-Kun Peng Sep 2018

Innovation, Firm Size Distribution, And Gains From Trade, Yi-Fan Chen, Wen-Tai Hsu, Shin-Kun Peng

Research Collection School Of Economics

We study a trade model with monopolistic competition a la Melitz (2003) that is standard except that firm heterogeneity is endogenously determined by firms innovating to enhance their productivities. We show that the equilibrium productivity and firm-size distributions exhibit power-law tails under rather general conditions on demand and technology. In particular, the emergence of the power laws is essentially independent of the underlying primitive heterogeneity among firms. We investigate the model’s welfare implications, and conduct a quantitative analysis of welfare gains from trade. We find that, conditional on the same trade elasticity and values of the common parameters, our model …

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Sharing Sequential Values In A Network, Ruben Juarez, Yu Ko Chiu, Jingyi Xue Sep 2018

Sharing Sequential Values In A Network, Ruben Juarez, Yu Ko Chiu, Jingyi Xue

Research Collection School Of Economics

Consider a sequential process where agents have individual values at every possible step. A planner is in charge of selecting steps and distributing the accumulated aggregate values among a number of agents. We model this process by a directed network, whereby each edge is associated with a vector of individual values. This model applies to several new and existing problems, e.g. developing a connected public facility and distributing total values received by surrounding districts, selecting a long-term production project and sharing final profits among partners of a firm, or choosing a machine schedule to serve different tasks and distributing total …

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Editorial For The Special Issue Entitled: New Advances In Spatial Econometrics: Interactions Matter, Nicolas Debarsy, Zhenlin Yang Sep 2018

Editorial For The Special Issue Entitled: New Advances In Spatial Econometrics: Interactions Matter, Nicolas Debarsy, Zhenlin Yang

Research Collection School Of Economics

This Regional Science and Urban Economics special issue collects together a subset of contributions presented in the 15th edition of the International Workshop in Spatial Econometrics and Statistics, which was organized by the Department of Economics of the University of Orléans (Laboratoire d’Economie d’Orléans – UMR CNRS 7322) on May 26-27 2016

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Comment On: Limit Of Random Measures Associated With The Increments Of A Brownian Semimartingale, Jia Li, Dacheng Xiu Sep 2018

Comment On: Limit Of Random Measures Associated With The Increments Of A Brownian Semimartingale, Jia Li, Dacheng Xiu

Research Collection School Of Economics

We thank the Editors’ invitation for the opportunity of contributing to this special issue as a celebration of Professor Jean Jacod’s seminal work originally written in 1994 (Jacod, 1994). This paper established general limit theorems for integrated volatility functionals, and provided theoretical tools that eventually changed the landscape of theoretical research concerning high-frequency data. This impact is also largely due to Professor Jacod’s continuous contribution to a broad variety of challenging issues in the area of high-frequency financial econometrics, including volatility estimation, jumps, and microstructure noise, as well as a large body of mathematical results collected in Jacod and Shiryaev …

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Spatial Dynamic Panel Data Models With Correlated Random Effects, Liyao Li, Zhenlin Yang Aug 2018

Spatial Dynamic Panel Data Models With Correlated Random Effects, Liyao Li, Zhenlin Yang

Research Collection School Of Economics

In this paper, M-estimation and inference methods are developed for spatial dynamic panel data models with correlated random effects, based on short panels. The unobserved individual-specific effects are assumed to be correlated with the observed time-varying regressors linearly or in a linearizable way, giving the so-called correlated random effects model, which allows the estimation of effects of time-invariant regressors. The unbiased estimating functions are obtained by adjusting the conditional quasi-scores given the initial observations, leading to M-estimators that are consistent, asymptotically normal, and free from the initial conditions except the process starting time. By decomposing the estimating functions into sums …

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Financial Bubble Implosion And Reverse Regression, Peter C. B. Phillips, Shu-Ping Shi Aug 2018

Financial Bubble Implosion And Reverse Regression, Peter C. B. Phillips, Shu-Ping Shi

Research Collection School Of Economics

Expansion and collapse are two key features of a financial asset bubble. Bubble expansionmay be modeled using a mildly explosive process. Bubble implosion may take several differentforms depending on the nature of the collapse and therefore requires some flexibility in modeling.This paper first strengthens the theoretical foundation of the real time bubble monitoringstrategy proposed in Phillips, Shi and Yu (2015a,b, PSY) by developing analytics and studyingthe performance characteristics of the testing algorithm under alternative forms of bubbleimplosion which capture various return paths to market normalcy. Second, we propose a newreverse sample use of the PSY procedure for detecting crises and …

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Has The Development Gap Between The Ethnic Minority And Majority Groups Narrowed In Vietnam?: Evidence From Household Surveys, Tomoki Fujii Aug 2018

Has The Development Gap Between The Ethnic Minority And Majority Groups Narrowed In Vietnam?: Evidence From Household Surveys, Tomoki Fujii

Research Collection School Of Economics

Using household data for rural northern Vietnam between 1993 and 2014, we find that the ethnic minority group continued to lag behind the majority group in various development indicators despite the overall improvement in living standards. Our regression and decomposition analyses show that the structural differences between the two groups are an important cause of persistent development gap. However, the nature of structural differences changed over time and no single source of structural difference explains the persistent gap. We argue that more minority‐appropriate policies are needed to lift poor minority households out of poverty further and reduce the development gap.

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Unified M-Estimation Of Fixed-Effects Spatial Dynamic Models With Short Panels, Zhenlin Yang Aug 2018

Unified M-Estimation Of Fixed-Effects Spatial Dynamic Models With Short Panels, Zhenlin Yang

Research Collection School Of Economics

It is well known that quasi maximum likelihood (QML) estimation of dynamic panel data (DPD) models with short panels depends on the assumptions on the initial values, and a wrong treatment of them will result in inconsistency and serious bias. The same issues apply to spatial DPD (SDPD) models with short panels. In this paper, a unified Mestimation method is proposed for estimating the fixed-effects SDPD models containing three major types of spatial effects, namely spatial lag, spatial error and space-time lag. The method is free from the specification of the distribution of the initial observations and robust against nonnormality …

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Bootstrap Lm Tests For Higher-Order Spatial Effects In Spatial Linear Regression Models, Zhenlin Yang Aug 2018

Bootstrap Lm Tests For Higher-Order Spatial Effects In Spatial Linear Regression Models, Zhenlin Yang

Research Collection School Of Economics

This paper first extends the methodology of Yang (J Econom 185:33-59, 2015) to allow for non-normality and/or unknown heteroskedasticity in obtaining asymptotically refined critical values for the LM-type tests through bootstrap. Bootstrap refinements in critical values require the LM test statistics to be asymptotically pivotal under the null hypothesis, and for this we provide a set of general methods for constructing LM and robust LM tests. We then give detailed treatments for two general higher-order spatial linear regression models: namely the model and the model, by providing a complete set of non-normality robust LM and bootstrap LM tests for higher-order …

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The Role Of Royalties In Resource Extraction Contracts, Robert F. Conrad, Robert Bryce Hool, Denis Nekipelov Aug 2018

The Role Of Royalties In Resource Extraction Contracts, Robert F. Conrad, Robert Bryce Hool, Denis Nekipelov

Research Collection School Of Economics

The manner in which governments charge mineral resource producers has been the subject of considerable debate. Income-based charges such as resource rent taxes have been advocated on the theory that royalties and other output-based charges create inefficiency by distorting production decisions. Using a principal-agent approach to resource contracts, separating asset ownership from asset use, we demonstrate that royalties can be efficient under conditions of certainty and also when there is uncertainty and asymmetric information. Royalties serve a key pricing purpose, signaling the marginal impact of extraction on the residual value of reserves and surrounding land or sea.

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Asymptotics And Bootstrap For Random-Effects Panel Data Transformation Models, Liangjun Su, Zhenlin Yang Jul 2018

Asymptotics And Bootstrap For Random-Effects Panel Data Transformation Models, Liangjun Su, Zhenlin Yang

Research Collection School Of Economics

This article investigates the asymptotic properties of quasi-maximum likelihood (QML) estimators for random-effects panel data transformation models where both the response and (some of) the covariates are subject to transformations for inducing normality, flexible functional form, homoskedasticity, and simple model structure. We develop a QML-type procedure for model estimation and inference. We prove the consistency and asymptotic normality of the QML estimators, and propose a simple bootstrap procedure that leads to a robust estimate of the variance-covariance (VC) matrix. Monte Carlo results reveal that the QML estimators perform well in finite samples, and that the gains by using the robust …

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Diagnostic Tests For Homoskedasticity In Spatial Cross-Sectional Or Panel Models, Badi H. Baltagi, Alain Pirotte, Zhenlin Yang Jul 2018

Diagnostic Tests For Homoskedasticity In Spatial Cross-Sectional Or Panel Models, Badi H. Baltagi, Alain Pirotte, Zhenlin Yang

Research Collection School Of Economics

We propose tests for homoskedasticity in spatial econometric models, based on joint or concentrated score functions and an Outer-Product-of-Martingale-Difference (OPMD) estimate of the variance of the joint or concentrated score functions. Versions of these tests robust against non-normality are also given. Asymptotic properties of the proposed tests are formally examined using a cross-section model and a panel model with fixed effects. Monte Carlo results show that the proposed tests based on the concentrated score function have good finite sample properties. Finally, the generality of the proposed approach in constructing tests for homoskedasticity is further demonstrated using a spatial dynamic panel …

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Regional Prevalence Of Health Worker Absenteeism In Tanzania, Tomoki Fujii Jul 2018

Regional Prevalence Of Health Worker Absenteeism In Tanzania, Tomoki Fujii

Research Collection School Of Economics

Absenteeism of health workers in developing countries is common and can severely undermine the reliability of health system. Therefore, it is important to understand where the prevalence of absenteeism is high. We develop a simple imputation method that combines a Service Delivery Indicators survey and a Service Provision Assessment survey to estimate the prevalence of absenteeism of health workers at the level of regions in Tanzania. The resulting estimates allow one to identify the regions in which the prevalence of absenteeism is significantly higher or lower than the national average and help policymakers determine the priority areas for intervention.

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Income Inequality, Productivity, And International Trade, Wen-Tai Hsu, Lin Lu, Pierre Picard Jul 2018

Income Inequality, Productivity, And International Trade, Wen-Tai Hsu, Lin Lu, Pierre Picard

Research Collection School Of Economics

This paper discusses the effect of income inequality on selection and aggregate productivity in a general equilibrium model with non-homothetic preferences. It shows the existence of a negative relationship between the number and quantity of products consumed by an income group and the earnings of other income groups. It also highlights the negative effect of a mean-preserving spread of income on aggregate productivity through the softening of firms’ selection. This effect is however mitigated in the presence of international trade. In a quantitative analysis, it is shown that an excessively large mean-preserving spread of income may harm the rich as …

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New Distribution Theory For The Estimation Of Structural Break Point In Mean, Liang Jiang, Xiaohu Wang, Jun Yu Jul 2018

New Distribution Theory For The Estimation Of Structural Break Point In Mean, Liang Jiang, Xiaohu Wang, Jun Yu

Research Collection School Of Economics

Based on the Girsanov theorem, this paper obtains the exact distribution of the maximum likelihood estimator of structural break point in a continuous time model. The exact distribution is asymmetric and tri-modal, indicating that the estimator is biased. These two properties are also found in the finite sample distribution of the least squares (LS) estimator of structural break point in the discrete time model, suggesting the classical long-span asymptotic theory is inadequate. The paper then builds a continuous time approximation to the discrete time model and develops an in-fill asymptotic theory for the LS estimator. The in-fill asymptotic distribution is …

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Boundary Limit Theory For Functional Local To Unity Regression, Anna Bykhovskaya, Peter C. B. Phillips Jul 2018

Boundary Limit Theory For Functional Local To Unity Regression, Anna Bykhovskaya, Peter C. B. Phillips

Research Collection School Of Economics

This article studies functional local unit root models (FLURs) in which the autoregressive coefficient may vary with time in the vicinity of unity. We extend conventional local to unity (LUR) models by allowing the localizing coefficient to be a function which characterizes departures from unity that may occur within the sample in both stationary and explosive directions. Such models enhance the flexibility of the LUR framework by including break point, trending, and multidirectional departures from unit autoregressive coefficients. We study the behavior of this model as the localizing function diverges, thereby determining the impact on the time series and on …

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Policy Innovations For Affordable Housing In Singapore: From Colony To Global City, Sock Yong Phang Jun 2018

Policy Innovations For Affordable Housing In Singapore: From Colony To Global City, Sock Yong Phang

Research Collection School Of Economics

Global cities today are facing fundamental challenges in relation to unaffordable housing and growing economic inequality. Singapore’s success in making home ownership possible for 90% of its population has attracted much attention internationally. This book represents a culmination of research by the author on key housing policy innovations for affordable housing. Housing policy changes were effected in the 1960s through reforms of colonial legislation and institutions dealing with state land acquisition, public housing, and provident fund savings. The comprehensive housing framework that was established enabled the massive resettlement of households from shophouses, slums and villages to high-rise government-built flats. In …

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Fair Division With Uncertain Needs, Jingyi Xue Jun 2018

Fair Division With Uncertain Needs, Jingyi Xue

Research Collection School Of Economics

Imagine agents having uncertain needs for a resource when the resource has to be divided before uncertainty resolves. In this situation, waste occurs when an agent's assignment turns out to exceed his realized need. How should the resource be divided in the face of possible waste? This is a question out of the scope of the existing rationing literature. Our main axiom to address the issue is no domination. It requires that no agent receive more of the resource than another while producing a larger expected waste, unless the other agent has been fully compensated. Together with conditional strict endowment …

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The Heterogeneous Effects Of The Minimum Wage On Employment Across States, Wuyi Wang, Peter C. B. Phillips, Liangjun Su Jun 2018

The Heterogeneous Effects Of The Minimum Wage On Employment Across States, Wuyi Wang, Peter C. B. Phillips, Liangjun Su

Research Collection School Of Economics

This paper studies the relationship between the minimum wage and the employment rate in the US using the framework of a panel structure model. The approach allows the minimum wage, along with some other controls, to have heterogeneous effects on employment across states which are classified into a group structure. The effects on employment are the same within each group but differ across different groups. The number of groups and the group membership of each state are both unknown a priori. The approach employs the C-Lasso technique, a recently developed classification method that consistently estimates group structure and leads to …

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Occupational Shortage And Labor Market Adjustments: A Theory Of Islands, Joanne Tan, Riccardo Zago Jun 2018

Occupational Shortage And Labor Market Adjustments: A Theory Of Islands, Joanne Tan, Riccardo Zago

Research Collection School Of Economics

Human Resources officers report occupational shortage to be the main cause of unfilled vacancies. Yet, it is not clear whether these are empty complaints or actually lead to effective wage and employment adjustments over time. By crossing data from the UK Employer Skill Survey with the UK Labor Force Survey, we show that shortage only leads to wage and employment adjustments for non-routine occupations in England, while no such adjustment occurs for routine occupations. This result is robust to several empirical specifications and varying levels of aggregation. Moreover, firms facing routine occupation shortage are more likely to outsource these vacancies, …

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Income And Subjective Well-Being: Evidence From Singapore's First National Non-Contributory Pension, Yanying Chen, Yi Jin Tan May 2018

Income And Subjective Well-Being: Evidence From Singapore's First National Non-Contributory Pension, Yanying Chen, Yi Jin Tan

Research Collection School Of Economics

We use a new monthly panel and a difference-in-differences strategy to study the effects of an exogenous permanent income shock on subjective well-being along previously unexplored dimensions. This permanent income shock is the introduction of Singapore’s first national non-contributory pension, the Silver Support Scheme. The pension improved the life satisfaction of recipients, and appeared to be driven by social, household income, and economic satisfaction. Consistent with the predictions of standard consumption-savings models, well-being improved when the shock was unanticipated (at announcement), but did not improve significantly further when the shock was anticipated (at disbursement). In addition, we find evidence that …

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When Does Limited Commitment Matter In A Production Economy?, Kyoung Jin Choi, Jungho Lee May 2018

When Does Limited Commitment Matter In A Production Economy?, Kyoung Jin Choi, Jungho Lee

Research Collection School Of Economics

We investigate the conditions under which the first-best allocation without commitment is sustainable in a production economy. While it is widely known in the literature that allowing capital accumulation creates a distortion, we find that it can help to sustain the first-best allocation. We also find that for a certain set of endowment economiesin which the efficient allocation is not sustainable, the efficient allocation becomes sustainable once we introduce a production technology with very small returns to scale orany returns to scale higher than that of the minimum value. In some cases, gains fromefficient resource allocation between agents can be …

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The Effect Of Non-Contributory Pensions On Labour Supply And Private Income Transfers: Evidence From Singapore, Yanying Chen, Yi Jin Tan May 2018

The Effect Of Non-Contributory Pensions On Labour Supply And Private Income Transfers: Evidence From Singapore, Yanying Chen, Yi Jin Tan

Research Collection School Of Economics

Non-contributory pensions are becoming increasingly prevalent worldwide. As their effects are likely to be context-dependent, evaluating their effects in a wide range of settings is important for establishing the external validity of the non-contributory pension literature. We use a new monthly panel dataset and a difference-in-differences strategy to study the effect of a new non-contributory pension in Singapore (the Silver Support Scheme or SSS) on labour supply, work expectations, private cash transfers, and expenditure, 1 year after its implementation. We find no evidence that receiving SSS payouts led to a fall in labour supply, work expectations, or the receipt of …

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A Dynamic Network Perspective On The Latent Group Structure Of Cryptocurrencies, Li Guo, Yubo Tao, Wolfgang Karl Hardle May 2018

A Dynamic Network Perspective On The Latent Group Structure Of Cryptocurrencies, Li Guo, Yubo Tao, Wolfgang Karl Hardle

Research Collection School Of Economics

In this paper, we study the latent group structure in cryptocurrencies market by forming a dynamic return inferred network with coin attributions. We develop a dynamic covariate-assisted spectral clustering method to detect the communities in dynamic network framework and prove its uniform consistency along the horizons. Applying our new method, we show the return inferred network structure and coin attributions, including algorithms and proof types, jointly determine the market segmentation. Based on the network model, we propose a novel "hard-to-value" measure using the centrality scores. Further analysis reveals that the group with a lower centrality score exhibits stronger short-term return …

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Maskin Meets Abreu And Matsushima, Yi-Chun Chen, Takashi Kunimoto, Yifei Sun, Siyang Xiong May 2018

Maskin Meets Abreu And Matsushima, Yi-Chun Chen, Takashi Kunimoto, Yifei Sun, Siyang Xiong

Research Collection School Of Economics

We study the classical Nash implementation problem due to Maskin (1999), but allow for the use of lottery and monetary transfer as in Abreu and Matsushima (1992, 1994). We therefore unify two well-established but somewhat orthogonal approaches of implementation theory. We first show that Maskin monotonicity is a necessary and sufficient condition for pure-strategy Nash implementation by a direct mechanism. Second, taking mixed strategies into consideration, we show that Maskin monotonicity is a necessary and sufficient condition for mixed-strategy Nash implementation by a finite (albeit indirect) mechanism. Third, we extend our analysis to implementation in rationalizable strategies. In contrast to …

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Determination Of Different Types Of Fixed Effects In Three-Dimensional Panels, Xun Lu, Ke Miao, Liangjun Su Apr 2018

Determination Of Different Types Of Fixed Effects In Three-Dimensional Panels, Xun Lu, Ke Miao, Liangjun Su

Research Collection School Of Economics

In this paper we propose a jackknife method to determine the type of fixed effects in three-dimensional panel data models. We show that with probability approaching 1, the method can select the correct type of fixed effects in the presence of only weak serial or cross-sectional dependence among the error terms. In the presence of strong serial correlation, we propose a modified jackknife method and justify its selection consistency. Monte Carlo simulations demonstrate the excellent finite sample performance of our method. Applications to two datasets in macroeconomics and international trade reveal the usefulness of our method.

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Investment And The Long Swings Of Unemployment, Hian Teck Hoon, Katsimi Margarita, Gylfi Zoega Apr 2018

Investment And The Long Swings Of Unemployment, Hian Teck Hoon, Katsimi Margarita, Gylfi Zoega

Research Collection School Of Economics

We estimate the relationship between investment and unemployment over the time period 1960-2015 in 20 OECD countries. While neoclassical growth theory typically assumes full employment – with no effect of investment on unemployment – we find that over our sample period covering more than five decades, a statistically significant negative relationship does exist: when investment fell, unemployment increased. When the time period is broken down into two sub-periods to take account of the Great Recession, we find that the estimated coefficient of investment is slightly smaller when the period 2001-2015 is added to the 1960-2000 period. We also find a …

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Asymptotic Inference About Predictive Accuracy Using High Frequency Data, Jia Li, Andrew J. Patton Apr 2018

Asymptotic Inference About Predictive Accuracy Using High Frequency Data, Jia Li, Andrew J. Patton

Research Collection School Of Economics

This paper provides a general framework that enables many existing inference methods for predictive accuracy to be used in applications that involve forecasts of latent target variables. Such applications include the forecasting of volatility, correlation, beta, quadratic variation, jump variation, and other functionals of an underlying continuous-time process. We provide primitive conditions under which a “negligibility” result holds, and thus the asymptotic size of standard predictive accuracy tests, implemented using a high-frequency proxy for the latent variable, is controlled. An extensive simulation study verifies that the asymptotic results apply in a range of empirically relevant applications, and an empirical application …

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