Economics Commons^™

What Is The Fallacy Of Approximation?, Matthew Hammerton, Sovan Patra

Research Collection School of Social Sciences

Many philosophers appeal to the “fallacy of approximation”, or “problem of second best”. However, despite the pervasiveness of such appeals, there has been only a single attempt to provide a systematic account of what the fallacy is. We identify the shortcomings of this account and propose a better one in its place. Our account not only captures all the contexts in which approximation-based reasoning occurs but also systematically explains the several different ways in which it can be in error.

Evaluation Of Unplanned Reattendances To The Pediatric Emergency Department: A Five-Year Study, Liying Toh, Jin Wee Lee, Siok Hoon Ang, Sashikumar Ganapathy, Janani D/O Nadarajan, Shu-Ling Chong

Research Collection School Of Economics

Background: Unplanned reattendances (UR) are an important quality indicator in the emergency department (ED). Understanding the risk factors associated with UR can aid clinicians in optimizing the allocation of time and resources, as well as targeted counselling for this specific group of patients. In this study, we aimed to compare patient characteristics between children who attended a pediatric emergency department (ED) with unplanned reattendances (UR) and those without UR. We also aimed to study the association between healthcare delivery factors such as timing of the attendance, patient load, changeover months for rotating junior doctors, presence of supervision, and rate of …

Estimating Firm-Level Production Functions With Spatial Dependence, Pao-Li Chang, Ryo Makioka, Bo Lin Ng, Zhenlin Yang

Research Collection School Of Economics

This paper proposes a three-stage efficient GMM estimation algorithm for estimating firm-level production functions given spatial dependence across firms due to supplier-customer relationships, sharing of input markets, or knowledge spillover. The procedure builds on Ackerberg, Caves and Frazer (2015) and Wooldridge (2009), but in addition, allows the productivity process to depend on the lagged output levels and lagged input usages of related firms, and spatially correlated productivity shocks across firms, where the set of related firms can differ across the three dimensions of spatial dependence. We establish the asymptotic properties of the proposed estimator, and conduct Monte Carlo simulations to …

Do Women Receive Worse Financial Advice?, Utpal Bhattacharya, Amit Kumar, Sujata Visaria, Jing Zhao

Research Collection Lee Kong Chian School Of Business

We arranged for trained undercover men and women to pose as potential clients and visit all 65 local financial advisory firms in Hong Kong. At financial planning firms, but not at securities firms, women were more likely than men to receive advice to buy only individual or only local securities. Female clients who signaled high confidence, high risk tolerance, or a domestic outlook were especially likely to receive this suboptimal advice. Our theoretical model explains these patterns as a result of statis-tical discrimination interacting with advisors’ incentives. Taste-based discrimination is unlikely to explain the results.

Social Institutions And Low Birth Rates, Christine Ho, Yutao Wang

Research Collection School Of Economics

We document three cross-sectional stylized facts on labor supply and family formation. First, female labor force participation (FLFP) and total fertility rates (TFRs) are much lower in Eastern societies compared to Western economies. Second, labor hours and the gender pay gap are much higher in the East than in the West. Third, parents invest more in schooling in Eastern societies compared to Western economies. To account for these features, we develop and estimate a rich heterogeneous-agent model with endogenous marriage, fertility, labor supply, and time and money investment in children. Estimates using data from South Korea and the United States …

Granulocyte Colony Stimulating Factor Promotes Scarless Tissue Regeneration, Jianhe Huang, Satish: Murphy Sati, Casey A. Spencer, Emmanuel Rapp, Stephen M. Prouty, Scott Korte, Olivia Ahart, Emily Sheng, Anna E. Kersh, Denis Leung, Thomas H. Leung, Leung, Denis H. Y.

Research Collection School Of Economics

Mammals typically heal with fibrotic scars, and treatments to regenerate human skin and hair without a scar remain elusive. We discovered that mice lacking C-X-C motif chemokine receptor 2 (CXCR2 knockout [KO]) displayed robust and complete tissue regeneration across three different injury models: skin, hair follicle, and cartilage. Remarkably, wild-type mice receiving plasma from CXCR2 KO mice through parabiosis or injections healed wounds scarlessly. A comparison of circulating proteins using multiplex ELISA revealed a 24-fold higher plasma level of granulocyte colony stimulating factor (G-CSF) in CXCR2 KO blood. Local injections of G-CSF into wild-type (WT) mouse wound beds reduced scar …

Machine Learning As Arbitrage: Can Economics Help Explain Ai?, Huahao Lu, Matthew Spiegel, Hong Zhang

Sim Kee Boon Institute for Financial Economics

Machine learning algorithms have shown to be remarkably successful tools for predicting asset returns. However, the underlying economic mechanisms behind their performance remain unclear. This paper proposes a model-based dynamic arbitrage trading strategy that combines economic and statistical nonstationarity to demystify this black box. In predicting stock returns based on 153 firm characteristics (anomalies), our strategy ranks anomalies similarly to neural networks in the cross-section. Overall, it accounts for approximately 87.9 bps monthly alphas of the high-minus-low portfolios selected by neural networks in the time series. When unpublished anomalies and microcap stocks are excluded from trading, this strategy can fully …

The Importance Of Sampling Frequency For Estimates Of Well-Being Dynamics, Stephen James Hoskins, David W. Johnston, Johannes S. Kunz, Michael A. Shields, Kevin E. Staub

ROSA Journal Articles and Publications

Using a high-frequency panel survey, we examine the sensitivity of estimated self-reported well-being (SWB) dynamics to using monthly, quarterly, and yearly data. This is an important issue if SWB is to be used to evaluate policy. Results from autoregressive models that account for individual-level heterogeneity indicate that the estimated persistence using yearly data is near zero. However, estimated persistence from monthly and quarterly data is substantial. We estimate that persistence to shocks typically lasts around six months and has a net present value of 75–80 per cent of the contemporaneous effect. Estimates are similar for different domains of SWB.

(Trade) War And Peace: How To Impose International Trade Sanctions, Gustavo De Souza, Naiyuan Hu, Haishi Li, Yuan Mei

Research Collection School Of Economics

What is the most cost-efficient way to impose trade sanctions against Russia? We build a quantitative model of international trade with input–output connections. Sanctioning countries choose import tariffs to simultaneously maximize their income and minimize Russia's income, with different weights placed on these objectives. We find, first, that for countries with low willingness to pay for sanctions against Russia, the most cost-efficient sanction is an approximately 20% tariff on all Russian products. Second, if countries are willing to pay at least US$0.70 for each US$1 drop in Russian welfare, an embargo on Russia's mining and energy products is the most …

Recruitment Of Cxcr4+ Type 1 Innate Lymphoid Cells Distinguishes Sarcoidosis From Other Skin Granulomatous Diseases, Satish Sati, Jianhe Huang, Anna E. Kersh, Parker Jones, Olivia Ahart, Christina Murphy, Stephen M. Prouty, Matthew L. Hedberg, Vaibhav Jain, Simon G. Gregory, Leung, Denis H. Y., John T. Seykora, Misha Rosenbach, Thomas H. Leung

Research Collection School Of Economics

Sarcoidosis is a multiorgan granulomatous disease that lacks diagnostic biomarkers and targeted treatments. Using blood and skin from patients with sarcoid and non-sarcoid skin granulomas, we discovered that skin granulomas from different diseases exhibit unique immune cell recruitment and molecular signatures. Sarcoid skin granulomas were specifically enriched for type 1 innate lymphoid cells (ILC1s) and B cells and exhibited molecular programs associated with formation of mature tertiary lymphoid structures (TLSs), including increased CXCL12/CXCR4 signaling. Lung sarcoidosis granulomas also displayed similar immune cell recruitment. Thus, granuloma formation was not a generic molecular response. In addition to tissue-specific effects, patients with sarcoidosis …

Several Us Trade ‘Deals’ Later, There Are Still More Questions Than Answers, Locknie Hsu

Research Collection Yong Pung How School Of Law

For ASEAN countries, the immediate question is not whether United States President Donald Trump’s tariffs are legal but how to get greater clarity about trade agreements, says SMU law professor Locknie Hsu.

Associative Networks In Decision Making, Jiangtao Li, Rui Tang, Mu Zhang

Research Collection School Of Economics

We present a model of associative networks that captures how a decision maker expands her consideration set through mental associations between alternatives. This model serves as a tool to understand the influence of association on decision making. As a proof of concept, we characterize this model within a random attention framework and demonstrate that all the relevant parameters are uniquely identifiable. Notably, in a novel choice domain where not all observable alternatives are available, the presence of unavailable alternatives can affect the choice frequencies of other alternatives through association.

Financial Crises, Bailouts And Monetary Policy In Open Economies, Yang Jiao

Research Collection School Of Economics

I jointly study the optimal bailout policy and monetary policy in open economies that borrow in foreign currency from international lenders. A policy dilemma emerges during financial crises. Policymakers trade off the benefit of more bailouts alleviating firms’ financial constraints against the cost of larger currency devaluation, which tightens firms’ financial constraints. I embed the optimal bailout in an otherwise standard “sudden stop” model with nominal rigidities. The model sheds light on the role of bailouts and currency mismatch in driving the exchange rate dynamics, firms’ balance sheets and economic recovery. Quantitatively, the model matches key business cycle moments. A …

Quantifying Delay Propagation In Airline Networks, Liyu Dou, Jakub Kastl, John Lazarev

Research Collection School Of Economics

We develop a framework for quantifying delay propagation in airline networks by integrating structural modeling and machine learning methods to estimate causal effects. Using a comprehensive dataset on actual delays and a model-selection algorithm (elastic net), we estimate a weighted directed graph of delay propagation for each major airline in the United States and establish conditions under which the propagation coefficients are causal. These estimates enable a decomposition of airline performance into "luck" and "ability." Our findings indicate that luck accounts for approximately 38% of the performance difference between Delta and American Airlines in our data. Additionally, we leverage these …

Recruitment Of Cxcr4+Type 1 Innate Lymphoid Cells Distinguishes Sarcoidosis From Other Skin Granulomatous Diseases, S. Sati, J. Huang, A.E. Kersh, P. Jones, O. Ahart, C. Murphy, S.M. Prouty, M.L. Hedberg, V. Jain, S.G. Gregory, Leung, Denis H. Y., J.T. Seykora, M. Rosenbach, T.H. Leung

Research Collection School Of Economics

Sarcoidosis is a multiorgan granulomatous disease that lacks diagnostic biomarkers and targeted treatments. Using blood and skin from patients with sarcoid and non-sarcoid skin granulomas, we discovered that skin granulomas from different diseases exhibit unique immune cell recruitment and molecular signatures. Sarcoid skin granulomas were specifically enriched for type 1 innate lymphoid cells (ILC1s) and B cells and exhibited molecular programs associated with formation of mature tertiary lymphoid structures (TLSs), including increased CXCL12/CXCR4 signaling. Lung sarcoidosis granulomas also displayed similar immune cell recruitment. Thus, granuloma formation was not a generic molecular response. In addition to tissue-specific effects, patients with sarcoidosis …

Family Size And Child Migration: Do Daughters Face Greater Trade-Offs Than Sons?, Christine Ho, Yutao Wang, Sharon Xuejing Zuo

Research Collection School Of Economics

We show that, conditional on family size, rural boys and girls are equally likely to migrate with parents in China. Nevertheless, daughters’ migration may still be compromised because they tend to have more siblings in societies with strong son preference, and larger families are more likely to leave all children behind. We find that a one unit increase in sibship size decreases the probability that a daughter migrates by 12.5 percentage points—with stronger effects when migration restrictions are more stringent—but has negligible effects on sons. The results suggest that gender-neutral migration constraints may generate gendered family size trade-offs.

Diverse Pathways To Permanent Childlessness In Singapore: A Latent Class Analysis, Yanwen Wang, Bussarawan Teerawichitchainan, Christine Ho

Research Collection School Of Economics

The proportions of adults reaching midlife without having children have been rising rapidly across the globe, particularly in Asia. However, little is known about the pathways to permanent childlessness within the region’s childless population. This study utilized latent class analysis (LCA) to typologize pathways to childlessness based on dynamic characteristics of multiple life domains (i.e., partnership, education, and occupation) among 489 childless Singaporeans aged 50 and above from a 2022 nationwide survey. Additionally, we utilized multinomial logistic regressions to examine the sociodemographic correlates of pathway profiles and Shannon’s entropy index to assess the heterogeneity in pathways to childlessness among successive …

Essays On Aging, Health, And Labor Market, Lanjie Wang

Dissertations and Theses Collection (Open Access)

This dissertation consists of four chapters on aging, health, and labor economics.

In the first chapter, we investigate the short-term impacts of unemployment on older workers in Singapore, a setting without public unemployment insurance. Using monthly panel data, we analyze dynamic impacts on income, spending, health, and subjective well-being over two years post-unemployment. We find substantial initial earnings losses with incomplete recovery, with income remaining 46.5% below pre-unemployment levels after 24 months. Despite this persistent income gap, consumption responses are modest and comparable to countries with strong social safety nets, suggesting robust self-insurance mechanisms. We observe increased retirement among married …

How Can Cbdcs Be Designed To Drive Financial Inclusion?, Heng Wang

Research Collection Yong Pung How School Of Law

As a new form of national currency, central bank digital currencies (CBDCs) hold the potential to be a transformative innovation that can enhance financial inclusion. However, the realization of this potential is very much contingent on their design. The realization of the benefit is also influenced by the barriers to financial inclusion that were identified in our first blog such as financial literacy, digital divide, and complexity.

A Robust Optimization Approach To Mechanism Design, Jiangtao Li, Kexin Wang

Research Collection School Of Economics

We study the design of mechanisms when the mechanism designer faces local uncertainty about agents’ beliefs. Specifically, we consider a designer who does not know the exact beliefs of the agents but is confident that her estimate is within ϵ of the beliefs held by the agents (where ϵ reflects the degree of local uncertainty). Adopting the robust optimization approach, we design mechanisms that incentivize agents to truthfully report their payoff-relevant information regardless of their actual beliefs. For any fixed ϵ, we identify necessary and sufficient conditions under which requiring this sense of robustness is without loss of revenue for …

Geographic Links And Predictable Returns, Zuben Jin, Frank Weikai Li

Research Collection Lee Kong Chian School Of Business

Using establishment-level data of U.S. public firms, we construct a novel measure of geographic linkage between firms. We show that the returns of geography-linked firms have strong predictive power for focal firm returns and fundamentals. This effect is distinct from other cross-firm return predictability and is not easily attributable to risk-based explanations. It is more pronounced for focal firms that receive lower investor attention, are more costly to arbitrage, and during high sentiment periods. The cross-firm information spillovers and return predictability are also stronger for geographic peers with economic linkages and with positive information. Our results are broadly consistent with …

Gradient Wild Bootstrap For Instrumental Variable Quantile Regressions With Weak And Few Clusters, Wenjie Wang, Yichong Zhang

Research Collection School Of Economics

We study the gradient wild bootstrap-based inference for instrumental variable quantile regressions in the framework of a small number of large clusters in which the number of clusters is viewed as fixed, and the number of observations for each cluster diverges to infinity. For the Wald inference, we show that our wild bootstrap Wald test, with or without studentization using the cluster-robust covariance estimator (CRVE), controls size asymptotically up to a small error as long as the parameter of endogenous variable is strongly identified in at least one of the clusters. We further show that the wild bootstrap Wald test …

The Interaction Effects Of Fintech And Bank Lending On Growth: Evidence From The Asean Region, Tan Swee Liang

Research Collection School Of Economics

This study examined the interaction effects of traditional bank lending and emerging fintech credit on economic growth in six ASEAN economies from 2013 to 2020. Using a two-way fixed effects (FE) model and the panel-corrected standard error (PCSE) method, the study found a statistically significant and positive interaction effect between bank lending and fintech credit. Specifically, fintech credit became increasingly important in shaping economic growth as bank lending ratios exceeded a certain threshold. Countries with high bank lending ratios experienced greater GDP per capita growth when accompanied by greater fintech credit. These findings suggest that policies supporting fintech development alongside …

Value Capture And Affordable Housing: Insights From Singapore, Sock Yong Phang

Research Collection School Of Economics

To explain the role of value capture in Singapore’s progress, I will first provide some background information on Singapore and its housing sector. I will then take you on a journey back to the 1960s to show how we established our present institutional arrangements for land and housing. I will next describe how housing policies have evolved over the past six decades in response to changing contexts. Finally, I will conclude with the fiscal implications of successful value capture. Where relevant, I will indicate how Singapore’s policies align with George’s views.

Digital Payments And Consumption: Evidence From The 2016 Demonetization In India, Sumit Agarwal, Pulak Ghosh, Jing Li, Tianyue Ruan

Research Collection School Of Economics

We study how consumer spending responds to digital payments, using the differential switch to digital payments across consumers induced by the sudden 2016 Indian Demonetization for identification. Usage of digital payments rose by 3.38 percentage points and monthly spending increased by 3% for an additional 10 percentage points in prior cash dependence. Spending remained elevated even when cash availability recovered. Robustness analyses show that the spending response is not driven by income shocks, credit supply, price changes, or consumers' moving to the formal market. We provide evidence that digital payments increase consumer spending due to subdued salience.

Cross-Exchange Crypto Risk: A High-Frequency Dynamic Network Perspective, Yifu Wang, Wanbo Lu, Min-Bin Liu, Rui Ren, Wolfgang Karl Hardle

Sim Kee Boon Institute for Financial Economics

Cross-exchange crypto trading presents inherent risks, particularly for centralized exchanges. Investors observe exacerbating crypto volatility and counterparty risk and would like to quantify these elements of crypto trades. The multiple exchanges require a multivariate view on the structures of risk spillover across exchanges. Here, a Multivariate Heterogeneous AutoRegression (MHAR) model is designed and analyzed, accommodating the stylized facts of crypto markets, including 24/7 trading and the long-memory effect on return variations. The proposed MHAR approach clearly reveals the intensity of interconnectedness among exchanges during extreme events, e.g., the Bitcoin market. Additionally, one observes extremely volatile eigenvector centralities of Futures Exchange …

Transportation, Healthcare Seeking, And Outcomes, Xiao Lin Ong

Dissertations and Theses Collection (Open Access)

Advancements in engineering and transportation technology have integrated commuting into modern living. Most studies on transportation infrastructure, such as roads and railways, focus on economic outcomes. This paper examines an overlooked outcome of transportation connectivity: access to medical care. We study the role transportation networks play in determining patients’ treatment location choices. Specifically, we aim to study 1) why patients travel to begin with, 2) how do patients choose where to go for treatment, and 3) how travel times can affect patients’ travel decisions. To do so, we develop a dynamic discrete choice, spatial model and provide empirical estimates. We …

Health Insurance And The Rise Of Women: Evidence From The New Cooperative Medical Scheme, Xingyu Bai

Dissertations and Theses Collection (Open Access)

Females are traditionally viewed as the primary providers of informal parental care in China, especially in rural areas. We investigate whether health insurance coverage in rural China, the New Cooperative Medical Scheme (NCMS), can unleash more female labor force participation by reducing the burden of informal parental care. Employing a heterogeneity-robust difference-in-differences estimation, we find that the NCMS has a significant positive impact on female labor supply, primarily in non-farm occupations. In contrast, we observe no significant changes in male labor supply. We explore the mechanism by showing that the NCMS significantly decreases both the provision and demand for parental …

Effect Of Catastrophic Medical Insurance On Healthcare Service Utilization And Quality, Ruiqi Ding

Dissertations and Theses Collection (Open Access)

China implemented catastrophic medical insurance (CMI) program to provide additional reimbursement for individuals requiring extensive healthcare services due to severe illnesses. This study empirically assesses the impact of the CMI program on the healthcare utilization and quality of care for severely ill patients, using medical insurance claim data from 2012 to 2018 in a capital city in China. The analysis yields the following conclusions: First, CMI decreased the medical expenditure of severe patients, but it had no impact on alleviating the financial burden. Second, CMI curbed abuse and saved medical resources, and in the meantime, it increased the use of …

Essays On Estimating Firm-Level Production Function With Spatial Dependence, Bo Lin Ng

Dissertations and Theses Collection (Open Access)

This dissertation consists of two chapters on the estimation of firm-level production functions when spatial effects are present. In joint work with Pao-Li Chang, chapter 1 focuses on the impacts of global value chains (GVC) on the firm-level outcomes of Singapore. First, we quantify Singapore’s participation in global value chains (GVC) using the export decomposition framework of Borin and Mancini (2019), before using these indicators to analyse how GVC participation affects sectoral-level valueadded and employment. We find that gross exports and foreign final demand have become more important for Singapore’s value-added, largely driven by the Services sectors. We then use …