Changes in public bike usage after the COVID-19 outbreak: A survey of Seoul public bike sharing users.

When the COVID-19 pandemic swept across the world, people tended to seek more individualized and viable transportation modes, such as a bicycle. In this study, we examined the factors influencing changes in public bike sharing (PBS) in Seoul, to assess this trend post-pandemic. We conducted an online survey of 1,590 Seoul PBS users between July 30 and August 7, 2020. Using a difference-in-differences analysis, we found that participants who were affected by the pandemic used PBS 44.6 h more than unaffected individuals throughout the year. In addition, we used a multinomial logistic regression analysis to identify the factors affecting changes in PBS usage. In this analysis, the discrete dependent variables of increased, unchanged, and decreased were considered, representing the changes in PBS usage after the COVID-19 outbreak. Results revealed that PBS usage increased among female participants during weekday trips such as commuting to work and when there were perceived health benefits of using PBS. Conversely, PBS usage tended to decrease when the weekday trip purpose was for leisure or working out. Our findings offer insight into PBS user behaviors within the context of the COVID-19 pandemic and present policy implications to revitalize PBS usage.

The effect of an information intervention on the career commitment of medical students: evidence from a randomized experiment.

Introduction: The needs-based shortage of healthcare workers is severe worldwide and it would be exacerbated if many medical students switch to other careers after graduation. Maintaining and improving the career commitment of medical students, which could be a feasible, effective, and scalable way to reduce the attrition rate, is essential in medical education. We designed a randomized experiment to test whether an information intervention based on role modeling could enhance medical students' career commitment. Methods: In the randomized experiment, the sample (N = 36,482) was divided into the treatment group (N = 18,070) and the control group (N = 18,412). The intervention information consisted of image-text messages on Zhong Nanshan, who is an inspiring role model for he went to the frontline of COVID-19 in the most critical circumstances and received praise and affirmation from the public. Α difference-in-differences model was employed to identify the effect of the information intervention. Heterogeneous treatment effects were identified using sub-sample analyses. Results: The results showed that the information intervention statistically significantly reduced medical students' dropout intention by 2.7 percentage points (95% CI: -0.037 to -0.016, t = -4.95, p < 0.001), equivalent to 14.6% of the control group mean. This estimate indicates that the information intervention could significantly increase the career commitment of medical students. Finally, male and senior students were influenced more than their female and junior counterparts, which can be explained by their relatively high dropout intention. Conclusion: Role model-based information intervention improves the career commitment of medical students. The underlying behavioral model is that, when students use a role model as their reference point, they consider dropout as a substantial welfare loss. Role modeling is an effective way to improve the career commitment of medical students, especially for males and senior students.

Understanding the globalization-crisis linkage: A "differenced” approach

The recent string of adverse global shocks (financial crisis, trade war, COVID-19, Ukraine war) poses a potential challenge to the well-known welfare enhancing effects of globalization, necessitating a better understanding of the longer run globalization-crisis linkage as opposed to its shorter run effects. Focusing on the Great Recession, we discover an evolving role of trade and financial openness from one that propagates and deepens the negative effects of crises to one that confirms its well-established contributions. Key to this is generating counterfactual output for open countries as if they were closed and examining the comparative impact of the crisis. © 2023 The Authors. Review of International Economics published by John Wiley & Sons Ltd.

E‐commerce and supply chain resilience during COVID‐19: Evidence from agricultural input e‐stores in China

COVID‐19 has caused major disruptions to agricultural supply chains around the world. Researchers and policy‐makers are interested in identifying means to reduce the disruptive effects caused by the pandemic. We investigate the impacts of COVID‐19 on the operation of e‐commerce stores (in short, e‐stores) specialising in agricultural inputs. The difference‐in‐differences method (DID) is employed to estimate the causal relationship between COVID‐19 and online sales of agricultural inputs using data from 54,244 agricultural input e‐stores registered in 118 prefecture‐level cities across 15 provinces and hosted on two major Chinese e‐commerce platforms. The results show that COVID‐19 led to a substantial growth in monthly sales of agricultural input e‐stores, and this growth of online sales varied across store scales and by types of agricultural inputs. In particular, e‐stores selling seeds and seedlings experienced a larger growth in sales than stores selling agricultural machinery and implements, and the mid‐ and larger‐scaled e‐stores experienced more growth of sales than micro‐ and small‐scaled e‐stores. Further analysis reveals that the growth of online sales of agricultural inputs was driven mainly by an increase in the quantity of customer orders (QCO). The findings of this paper underscore the importance of e‐commerce in ensuring the resilience of the agricultural supply chain during the pandemic period.

The effect of lockdown on students' performance: A comparative study between Italy, Sweden and Turkey.

During the first months of the COVID-19 outbreak, countries adopted different strategies in order to mitigate the effects of the pandemic, ranging from recommendations to limit individual movement to severe lockdown measures. Regarding higher education, university studies were shifted to digital solutions in most countries. The sudden move to online teaching affected students differently, depending on the overall mitigation strategies applied. Severe lockdown and closure measures caused a disruption of their academic and social interactions. In contrast, recommendations to limit activities probably did not change students' life to a great extent. The heterogeneity of the policies adopted in three countries (Italy, Sweden and Turkey) gives us an opportunity to assess the effects of lockdown measures due to the COVID-19 pandemic on university students' performance. We employ a difference-in-differences approach by exploiting the fact that Italy and Turkey experienced national lockdowns, while Sweden never applied nationwide mandatory restrictive policies. We use administrative data from universities in the three countries to estimate the probability to pass exams after the spread of COVID-19 pandemic (and the shift to distance education), with respect to the previous comparable period. We find that the pass rate decreased with the shift to online teaching. However, lockdown measures, especially if very restrictive as those applied in Italy, helped to compensate such negative effect. A possible explanation is that students took advantage of the huge increase in the time available for their studies, given the impossibility to carry out any activity outside the home.

Methodological considerations for estimating policy effects in the context of co-occurring policies.

Understanding how best to estimate state-level policy effects is important, and several unanswered questions remain, particularly about the ability of statistical models to disentangle the effects of concurrently enacted policies. In practice, many policy evaluation studies do not attempt to control for effects of co-occurring policies, and this issue has not received extensive attention in the methodological literature to date. In this study, we utilized Monte Carlo simulations to assess the impact of co-occurring policies on the performance of commonly-used statistical models in state policy evaluations. Simulation conditions varied effect sizes of the co-occurring policies and length of time between policy enactment dates, among other factors. Outcome data (annual state-specific opioid mortality rate per 100,000) were obtained from 1999 to 2016 National Vital Statistics System (NVSS) Multiple Cause of Death mortality files, thus yielding longitudinal annual state-level data over 18 years from 50 states. When co-occurring policies are ignored (i.e., omitted from the analytic model), our results demonstrated that high relative bias (> 82%) arises, particularly when policies are enacted in rapid succession. Moreover, as expected, controlling for all co-occurring policies will effectively mitigate the threat of confounding bias; however, effect estimates may be relatively imprecise (i.e., larger variance) when policies are enacted in near succession. Our findings highlight several key methodological issues regarding co-occurring policies in the context of opioid-policy research yet also generalize more broadly to evaluation of other state-level policies, such as policies related to firearms or COVID-19, showcasing the need to think critically about co-occurring policies that are likely to influence the outcome when specifying analytic models.

Does regional integration improve economic resilience? Evidence from urban agglomerations in China

Under the dual pressure of "slow-burn" challenges and acute shocks, increasing economic resilience is gaining attention around the world to ensure the security and stability of economic activities. With the goal of achieving sustainable development, the China is exploring an innovative, coordinated, green, open, shared and secure development path for the regional economy. Using panel data for 241 cities at the prefecture level and above in China from 2010 to 2019, this research considers urban agglomeration planning as a quasi-natural experiment of regional integration and use a difference-in-differences method to explore the effect of regional integration on economic resilience. The results show the following. 1) Regional integration does improve economic resilience after various robustness tests. 2) The policy effect of regional integration on economic resilience varies by time, region, and urban structure. 3) Urban size structure and industrial structure are important ways in which regional integration affects economic resilience. Our findings enrich the theoretical study of the relationship between regional integration and economic resilience and provide a new path to improve regional economic resilience and achieve sustainable development.

Crisis and the welfare state: the role of public employment services for job placement and the Danish flexicurity system during COVID-19

Denmark is a Nordic welfare state with local government autonomy in public service provision related to workfare policies. We use a policy experiment that re-opened on-site public employment services after the first COVID-19 lockdown in a spatially staggered manner to provide evidence on the effect of public employment services on job placement during a crisis. Early re-opening of on-site public employment services is associated with a better local labour market performance. It particularly benefits low-skilled unemployed and rural areas with specific sector mixes and demographic structures, why workfare-oriented welfare state arrangements remain important to counter social and regional imbalances.

Effect of the COVID-19 Pandemic on CO2 Emissions in India

We assess the effect of the COVID-19 pandemic on CO2 emissions in India. We study the impact of COVID-19–induced control measures on the major contributors of CO2 emissions by using a difference-in-differences model and eliminating the lockdown effect. We find that all the major contributors except for industrial emissions were significantly reduced due to the COVID-19 pandemic. © 2022, Asia-Pacific Applied Economics Association. All rights reserved.

Entrepreneurial efforts and opportunity costs: evidence from twitch streamers

With the rise of digital platforms, individuals' possibilities to generate income have increased drastically. In this context, we present digital content creation as a form of (digital) entrepreneurship that is characterized by potentially high but also uncertain revenues. As the cost structure of content creation mostly depends on opportunity costs, it stands in contrast to other popular platform-work options. We demonstrate how a stark and unexpected reduction in opportunity costs affects the actual decision to produce digital content. Exploiting the first wave of the COVID-19 pandemic, we measure how individuals (streamers) who operate on a live streaming platform, respond to a sudden change in external factors while accounting for individual differences in initial conditions. We observe intensified efforts across the spectrum of streamers and find particularly strong reactions from newcomer streamers. We further show that only the most successful newcomers sustain their increased efforts even when opportunity costs start to rise again. Our results are consistent with the initial assumption that an individual's decision on taking up or intensifying entrepreneurial efforts on digital platforms is strongly affected by their opportunity costs. The results further imply that there is a large potential in individuals who might be willing to become entrepreneurs but are restricted by external conditions. As platform-based digital entrepreneurship offers high flexibility and very low entry barriers, measures for lowering opportunity costs could therefore help to unleash this potential. To maintain a steady influx of new talents, content platforms should increase their support for smaller creators and policymakers should provide easily accessible platforms to ease the way into entrepreneurship for these individuals. © 2023, The Author(s).

Effects of non-compulsory and mandatory COVID-19 interventions on travel distance and time away from home, Norway, 2021.

BackgroundGiven the societal, economic and health costs of COVID-19 non-pharmaceutical interventions (NPI), it is important to assess their effects. Human mobility serves as a surrogate measure for human contacts and compliance with NPI. In Nordic countries, NPI have mostly been advised and sometimes made mandatory. It is unclear if making NPI mandatory further reduced mobility.AimWe investigated the effect of non-compulsory and follow-up mandatory measures in major cities and rural regions on human mobility in Norway. We identified NPI categories that most affected mobility.MethodsWe used mobile phone mobility data from the largest Norwegian operator. We analysed non-compulsory and mandatory measures with before-after and synthetic difference-in-differences approaches. By regression, we investigated the impact of different NPI on mobility.ResultsNationally and in less populated regions, time travelled, but not distance, decreased after follow-up mandatory measures. In urban areas, however, distance decreased after follow-up mandates, and the reduction exceeded the decrease after initial non-compulsory measures. Stricter metre rules, gyms reopening, and restaurants and shops reopening were significantly associated with changes in mobility.ConclusionOverall, distance travelled from home decreased after non-compulsory measures, and in urban areas, distance further decreased after follow-up mandates. Time travelled reduced more after mandates than after non-compulsory measures for all regions and interventions. Stricter distancing and reopening of gyms, restaurants and shops were associated with changes in mobility.

Population well-being and the COVID-19 vaccination program in Chile: evidence from Google Trends.

OBJECTIVE: We analyze the dynamics of the mental well-being of the Chilean population in response to the progress of the vaccination strategy implemented by the government. STUDY DESIGN: This study aims at investigating the possibility of using Google Trends as an instrument for tracking mental well-being of the Chilean population. METHODS: We use the volume of searches for keywords in Google Trends (GT) related to Anguish, Anxiety, Depression, and Stress as a proxy for population well-being. Using event study methods, we analyze social attention reactions to news about the vaccination program. We implement a Difference-in-Difference-in-Differences estimation to estimate changes in population welfare by socio-economic status induced by the progress of inoculation. RESULTS: We show that social attention to mental health problems is sensitive to news about the vaccination program. Moreover, and most importantly, we find that mental well-being responds positively to the percentage of inoculated people. This phenomenon appear to be permanent and affected by socio-economic status, with the wealthier population experiencing greater improvements than the less wealthy. CONCLUSIONS: During the COVID-19 vaccination program in Chile, social attention to mental health problems appears to be sensitive to news about the vaccination program. There is also strong evidence of socio-economic status-induced heterogeneity in population responses to program implementation. The above phenomena appears to be permanent and cannot be attributed to either socio-economic segregation in access to vaccines or to the highly stratified schedule of the vaccination program.

Failing Young and Temporary Workers? the Impact of a Disruptive Crisis on a Dual Labour Market

We study the impact of the pandemic crisis using monthly data covering the universe of individuals registered as unemployed in mainland Portuguese municipalities, complemented with electronic payments, linked employer-employee data, and furlough records. Event study designs identify a sharp increase in unemployment, driven mostly by termination of temporary contracts, and a decrease in new job placements. With triple difference-in-differences, we show that the effects are stronger in more dual municipal labour markets, i.e. with a higher share of temporary jobs, concentrated in young workers and middle educated individuals. The asymmetries are exacerbated by the duality of the municipal labour market. © 2023 Walter de Gruyter GmbH, Berlin/Boston 2023.

Impact of COVID-19 Prevention and Control Measures on Expressway Transportation in Guangdong-Hong Kong-Macao Greater Bay Area

Under the background of normalized COVID-19 prevention and control, regional epidemics occur frequently in China. How to quantify the impact of COVID-19 prevention and control measures on economic operation and passenger and freight transportation has become an urgent problem. To this end, we design a calculation method for expressway transportation indicators, propose the level and stage division process of COVID-19 prevention and control measures, and then establish a difference-in-difference model to further analyze their impact on expressway transportation indicators. Taking major cities in the Guangdong-Hong Kong-Macao Greater Bay Area as an example, case studies are conducted based on the expressway toll data and COVID-19 prevention and control information from May 2020 to April 2022. The results show that in the level I (strengthened) stage, the passenger vehicle flow has dropped significantly, the drop in each case is between 8% and 27%, and the freight indicators have not changed significantly. In Shenzhen and Dongguan, both passenger and freight indicators dropped sharply in the level II (strict) stage. Passenger vehicle flow in the two cities dropped by 46.3% and 33.7%, and truck flow by 42.7% and 27.6%, respectively, and cargo and turnover decreased as much as truck flow. The average inter- city distance of expressway passenger cars has a downward trend under the level I stage, but under the level II stage, the average inter-city distance of passenger cars and trucks has increased significantly. This study can provide a certain reference value for the formulation and implementation of COVID-19 prevention and control measures in cities and urban agglomerations. © 2022 Science Press. All rights reserved.

The impact of sudden public events and fiscal policy relief on the financing constraints of small and medium enterprises: a quasi-natural experiment during COVID-19

Using data on Chinese GEM-listed companies from the first quarter of 2018 to the second quarter of 2022, we examine the impact of COVID-19 on SMEs' financing constraints and the moderating effect of fiscal and tax incentives using the difference-in-differences method (DID). The results indicate that the COVID-19 shock severely affected SMEs' financing constraints, and this effect is more pronounced among firms in industries particularly sensitive to COVID-19, such as transportation, catering, accommodation, culture, and entertainment. A further analysis shows that tax incentives and fiscal subsidies have differing moderating effects, with the former alleviating SMEs' financing constraints and the latter having only a relatively limited effect. This finding provides direct micro-level evidence for understanding the impact of COVID-19 on financing constraints and provides insights for promoting the optimization of fiscal support policies for SMEs. © 2023 Informa UK Limited, trading as Taylor & Francis Group.

Deregulation and green innovation: Does cultural reform pilot project matter

Green innovation is an important driving force for sustainable development. However China often imposes a wide variety of government regulations on green innovation One important reason behind these government regulations is the confinement of the cultural market. However, does this confinement actually affect the green innovation in China? By employing a 278 Chinese cities' dataset, we examine the effect of cultural reform pilot project on green innovation. Through the spatial difference-in-difference approach with the time trend, our results show that cultural reform pilot project (CRPP) is a significant determinist affecting the green innovation in China. Specifically, implementing CRPP promote green innovation in pilot cities which resulting from labour productivity exaltation, marketization rate increasing. The CRPP also have a spatial ripple effect which resulting from economic density promotion. Furthermore, the green innovation promotion is greater in cities which participating into World Technopolis Association, being included in the National Historical and Cultural Cities List and having high political hierarchy. Our conclusions still robustness after adopting a series of tests and alternative analyses. This paper not only provide evidence for the further implementation of cultural reform pilot project nationwide, but also provide policy implications on sustainable development in the post Covid-19 era. © 2023 Economic Society of Australia, Queensland

Assessing the Impact of the Covid-19 on the US Airline Market Using an Instrumental Variable and a DID Empirical Strategy

In this paper, we examine the affects of COVID-19 and related policies on the aviation industry. Using archival data from the John Hopkins Coronavirus Resource Center, Department of Transportation Statistics, and the COVID-19 U.S. State Policy database, and an instrumental variable and a difference-in-differences empirical strategy, we find that COVID-19 severity is negatively correlated with both the mean ticket price and the number of passengers for the four major airlines in the US, and that the implementation of COVID-19 control policies is positively correlated with the mean ticket price, while negatively correlated with the number of passengers. © 2022 ACM.

The Effect of Proximity to Universities on House Prices after the COVID Outbreak

COVID-19 has made virtual interactions an integral part of learning modes. This made it possible for college students to live further away from school than before, which might change the house price neighboring universities. This article studies the effect of proximity to school on house prices after the COVID-19 outbreak using a non-parametric difference-in-differences approach with property-level transaction data surrounding 128 universities in the U.S. The results show that house prices within 0.5 miles of universities experienced a maximum decrease of approximately 7% after three months of the outbreak. The effects vary for universities that implemented different teaching modes of in-person, hybrid, and online. Since house prices are important indicators for local economic conditions, the results help local homeowners, investors, and governments in their decision-making processes. © 2023 by the author.

Lockdown Without Loss? A Natural Experiment of Net Payoffs from COVID-19 Lockdowns: JPP&M

Lacking a federal policy to control the spread of COVID-19, state governors ordered lockdowns and mask mandates, at different times, generating a massive natural experiment. The authors exploit this natural experiment to address four issues: (1) Were lockdowns effective in reducing infections? (2) What were the costs to consumers? (3) Did lockdowns increase (signaling effect) or reduce (substitution effect) consumers' mask adoption? (4) Did governors' decisions depend on medical science or nonmedical drivers? Analyses via difference-in-differences and generalized synthetic control methods indicate that lockdowns causally reduced infections. Although lockdowns reduced infections by 480 per million consumers per day (equivalent to a reduction of 56%), they reduced customer satisfaction by 2.2%, consumer spending by 7.5%, and gross domestic product by 5.4% and significantly increased unemployment by 2% per average state by the end of the observation period. A counterfactual analysis shows that a nationwide lockdown on March 15, 2020, would have reduced total cases by 60%, whereas the absence of any state lockdowns would have resulted in five times more cases by April 30. The average cost of reducing the number of cases by one new infection was about $28,000 in lower gross domestic product.

Using social media data to assess the impact of COVID-19 on mental health in China.

BACKGROUND: The outbreak and rapid spread of coronavirus disease 2019 (COVID-19) not only caused an adverse impact on physical health, but also brought about mental health problems among the public. METHODS: To assess the causal impact of COVID-19 on psychological changes in China, we constructed a city-level panel data set based on the expressed sentiment in the contents of 13 million geotagged tweets on Sina Weibo, the Chinese largest microblog platform. RESULTS: Applying a difference-in-differences approach, we found a significant deterioration in mental health status after the occurrence of COVID-19. We also observed that this psychological effect faded out over time during our study period and was more pronounced among women, teenagers and older adults. The mental health impact was more likely to be observed in cities with low levels of initial mental health status, economic development, medical resources and social security. CONCLUSIONS: Our findings may assist in the understanding of mental health impact of COVID-19 and yield useful insights into how to make effective psychological interventions in this kind of sudden public health event.