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Pharmaceutical firms typically enjoy market exclusivity for new drugs from concurrent protection of the underlying invention (through patents) and the clinical trials data submitted for market approval (through data exclusivity). Patent invalidation during drug development renders data exclusivity the sole source of protection and shifts the period of market exclusivity at the project level. Patent invalidation therefore constitutes a natural experiment that allows us to causally identify how the duration of market exclusivity affects firms' incentives to innovate. In instrumental variables regressions we quantify the effect of a one-year reduction in expected market exclusivity on the likelihood of drug commercialization. We provide first estimates of the responsiveness of R&D investments to market exclusivity expectations and hereby inform the ongoing policy debate on the regulation of intellectual property rights in the pharmaceutical industry.

Leveraging China’s 2013 anti-corruption campaign (the Campaign) as a quasi-natural experiment and a difference-in-differences (DID) research design, we examine which of the three motives (value relevancy, risk management, or altruism) better explain a firm’s corporate social responsibility (CSR) activities. Our findings suggest that, after the Campaign and conditional on the level of firm corruption-related expenses, firms generally engage in more CSR, which supports the value relevance motive of CSR. Additional analyses suggest that the positive impact of the Campaign on CSR is more salient when: 1) the Campaign is effective in the province in which a firm is located; 2) the financialization level of a province in which a firm is located is high; 3) firms have more political connections interruption in the Campaign; 4) firms have high operating risk; 5) firms are more capable of conducting CSR activities; or 6) the extent of firms’ corporate governance is excellent.

This paper studies the persistent effects of short-term peer exposure on long-run performance in a college setting. I exploit the random assignment of undergraduates to peer groups during a mandatory orientation week and track the students’ performance over four years (until graduation). Assignment to orientation week groups with high levels of peer ability is associated with lower performance during the first year at college and a higher probability of early dropout. These adverse effects are driven entirely by the exposure of low-ability students to high-ability peers. Beyond the first year, exposure to higher peer ability during the orientation week negatively affects selection into the college’s most popular major (business administration) and final grade point average. Taken together, the findings suggest that the composition of short-term peer groups matters for individual choices and long-run performance outcomes. This paper was accepted by Yan Chen, decision analysis.

Does international terrorism affect attitudes toward refugees? Does terrorism mobilize the public to pressure legislators to restrict refugee policy? Are these effects long- or short-lived? To answ...

We examine the impact of China's adoption of the logistics service standardization (LSS) as an exogenous shock on firm innovation. The results show that patents obtained by firms located in LSS cities after the reform increased more significantly compared to firms located in non-LSS cities. The findings are robust to alternative types of patents obtained, the number of patent applications, propensity score matched samples, accounting for selection bias, and placebo tests. Additional analyses suggest that the channels for the positive impact of the LSS on innovation are enhanced product market competition, lowered financial constraints, and reduced operating risk. In cross-sectional analyses, we document that the positive impact of the LSS on innovation is more salient for firms with distant supply chain partners, low inventory turnover, low production efficiency, high product potential, large government subsidies, and more bank loans.

Prior studies show infrastructural improvements impact property values positively. The effect is often reflected soon after the announcement and continues until the project is complete. These studies, however, are primarily set in developed countries. Emerging markets pose unique risks where uncertainty around implementation and funding could dampen these positive effects significantly. We utilize a quasi-natural experiment around an inner-city road redesign and improvement project in Bangalore, the fastest growing city in India. We exploit the difference-in-difference regression approach to examine the project’s impact on residential and commercial property values around two sets of geographically proximate roads, one of which was chosen for the redesign. Unlike in developed countries, we find that property values are unaffected by the announcement when uncertainty is the highest but start reflecting the positive value of the infrastructure once construction starts and show significant gains upon completion. Our findings carry important policy implications for structuring value capture strategies in emerging markets.

Summary Background Universal testing and treatment (UTT) for all people living with HIV has only been assessed under experimental conditions in cluster-randomised trials. The public health effectiveness of UTT policies on the HIV care cascade under real-world conditions is not known. We assessed the real-world effectiveness of universal HIV treatment policies that were implemented in Zambia on Jan 1, 2017. Methods We used data from Zambia's routine electronic health record system to analyse antiretroviral therapy (ART)-naive adults who newly enrolled in HIV care up to 1 year before and after the implementation of universal treatment (ie, Jan 1, 2016, to Jan 1, 2018) at 117 clinics supported by the Centre for Infectious Disease Research in Zambia. We used a regression discontinuity design to estimate the effects of implementing UTT on same-day ART initiation, ART initiation within 1 month, and retention on ART at 12 months (defined as clinic attendance 9–15 months after enrolment and at least 6 months on ART), under the assumption that patients presenting immediately before and after UTT implementation were balanced on both measured and unmeasured characteristics. We did an instrumental variable analysis to estimate the effect of same-day ART initiation under routine conditions on 12-month retention on ART. Findings 65 673 newly enrolled patients with HIV (40 858 [62·2%] female, median age 32 years [IQR 26–39], median CD4 count 287 cells per μL [IQR 147–466]) were eligible for inclusion in the analyses; 31 145 enrolled before implementation of UTT, and 34 528 enrolled after UTT. Implementation of universal treatment increased same-day ART initiation from 41·7% to 74·8% (risk difference [RD] 33·1%, 95% CI 30·5–35·7), ART initiation by 1 month from 69·6% to 87·0% (RD 17·4%, 15·5–19·3), and 12-month retention on ART from 56·2% to 63·3% (RD 7·1%, 4·3–9·9). ART initiation rates became more uniform across patient subgroups after implementation of universal treatment, but heterogeneity in 12-month retention on ART between subgroups was unchanged. Instrumental variable analyses indicated that same-day ART initiation in routine settings led to a 15·8% increase (95% CI 12·1–19·5) in 12-month retention on ART. Interpretation UTT policies implemented in Zambia increased the rapidity and uptake of ART, as well as retention on ART at 12 months, although overall retention on ART remained suboptimal. UTT policies reduced disparities in treatment initiation, but not 12-month retention on ART. Natural experiments reveal both the anticipated and unanticipated effects of real-world implementation and indicate the need for new strategies leveraging the short-term effects of UTT to cultivate long-term treatment success. Funding National Institutes of Health.

The pollution emissions trading system (PETS) pilot policy is China's first large-scale implementation of market-based environmental regulations; whether it can reduce pollution emissions and improve the export competitiveness is crucial for China to achieve the coordinated development of environment and economy. Based on the panel data of Chinese listed companies from 2003 to 2016, this paper considers the PETS pilot policy as a natural experiment, and investigates the impact of the policy on export products' quality using the difference-in-difference (DID) model. We found that (1) the PETS pilot policy has significantly improved the quality of listed companies' export products. (2) Technological innovation plays a partial intermediary role in promoting export products' quality by the PETS pilot policy; the "Porter Hypothesis" has been verified in China. (3) When the listed companies with different characteristics face the PETS pilot policy, the quality of their export products will show a differentiated development trend. Based on the above research conclusions, we put forward corresponding recommendations for China to realize the coordinated development of environment and trade.

Integrated strategies of community health promotion (ISCHP) are based on intersectoral collaborations using the Health in All Policies approach to address determinants of health. While effects on health determinants have been shown, evidence on the effectiveness of ISCHP on health outcomes is scarce. The aim of this study is to assess the long-term effects of ISCHP on diabetes mellitus mortality (DMM) in German communities. A nonrandomized evaluation based on secondary county-level official data (1998–2016) was performed. In April 2019, 149 communities in Germany with ISCHP out of 401 were identified. Communities with

Background COVID-19, a respiratory disease caused by the SARS-CoV-2 virus, emerged in 2019 and led to a worldwide pandemic in 2020. The COVID-19 pandemic has been a massive natural experiment in the formation of mitigation strategies to prevent cases and to provide effective healthcare for those afflicted. Regional differences in the impact of the pandemic on morbidity and mortality have been driven by political and regional differences in the coproduction of public health and social policy. We explored the United States (US) experience of COVID-19 for trends and correlations with other nations and also at the national, regional, state and local levels. Objective To identify geographic and temporal trends in the spread of COVID-19 in the United States. Methods Population data on COVID-19 cases and mortality were acquired on a daily basis from multiple publicly available databases, including the New York Times and Johns Hopkins University. At each geographic level (national, state and county), geographic entities’ reported cases were evaluated for correlations using linear least-squares methods to identify patterns of correlation in the cases independent of scale. We evaluated for two specific characteristics: (i) the nature of the curvature of the line linking across percentile scores, ranging from concave to convex and (ii) the area under this curve, indicating how effectively a selected region (nation, state and county) is linked to its entire containing unit (world, country and state). We used this approach to identify three distinct COVID behavior phenotypes, each of which consisted of a number of states in the USA. Results We found that COVID activity in the USA follows a unique trend compared to other countries and that within the USA during the first year of the pandemic, three initial COVID phenotypes emerged: (i) the metropolitan outbreak (early outbreak phenotype); (ii) the regional outbreak (summer peak phenotype) and (iii) trans-regional outbreak (fall/winter peak phenotype), which, taken in sum, represent the overall USA national trend. Each phenotype has specific behavioral characteristics and is composed of a cluster of different states experiencing different conditions. Conclusion Our findings suggest a new opportunity for public health strategy in the pandemic, namely to apply targeted public health approaches to address the specific needs of each phenotype. In the future, we should create databases that capture key health and hardship data elements at the smallest geographic level possible and use these to track trends, predict the future and apply targeted coproduction approaches to more effectively and efficiently safeguard population health, economic vitality and social well-being.

Governments are required to be fair in regulating market players, but their behaviors are often distorted by political connections with firms. In this study, we use the natural experiment of overcapacity reduction in China's industrial firms to examine to what extent their ownership matters in regulatory stringency. State-owned enterprises (SOEs) were significantly less likely than private firms to reduce their overcapacity. Furthermore, SOEs with more personnel redundancy and less degree of diversification in more competitive industries were less likely to meet central mandates. These results suggest that selective policy implementation helps to meet policy purposes albeit with unintended consequences.

Introduction Despite the growing recognition of the importance of neighborhood conditions for cardiometabolic health, causal relationships have been difficult to establish owing to a reliance on cross-sectional designs and selection bias. This is the first natural experiment to examine the impact of neighborhood revitalization on cardiometabolic outcomes in residents from 2 predominantly African American neighborhoods, one of which has experienced significant revitalization (intervention), whereas the other has not (comparison). Methods The sample included 532 adults (95% African American, 80% female, mean age=58.9 years) from 2 sociodemographically similar, low-income neighborhoods in Pittsburgh, PA, with preintervention and postintervention measures (2016 and 2018) of BMI, diastolic and systolic blood pressure, HbA1c, and high-density lipoprotein cholesterol and covariates. Data were collected in 2016 and 2018 and analyzed in 2020. Results Difference-in-difference analyses showed significant improvement in high-density lipoprotein cholesterol in intervention residents relative to that in the comparison neighborhood (β=3.88, 95% CI=0.47, 7.29). There was also a significant difference-in-difference estimate in diastolic blood pressure (β=3.00, 95% CI=0.57, 5.43), with residents of the intervention neighborhood showing a greater increase in diastolic blood pressure than those in the comparison neighborhood. No statistically significant differences were found for other outcomes. Conclusions Investing in disadvantaged neighborhoods has been suggested as a strategy to reduce health disparities. Using a natural experiment, findings suggest that improving neighborhood conditions may have a mixed impact on certain aspects of cardiometabolic health. Findings underscore the importance of examining the upstream causes of health disparities using rigorous designs and longer follow-up periods that provide more powerful tests of causality.

Growing literature points to the effectiveness of leveraging social interactions and nudges to spur adoption of prosocial behaviors. This study investigates a large-scale behavioral intervention designed to actively leverage social learning and peer interactions to encourage adoption of residential solar photovoltaic systems. Municipalities choose a solar installer offering group pricing and undertake an informational campaign driven by volunteer ambassadors. We find a causal treatment effect of 37 installations per municipality from the campaigns and no evidence of harvesting or persistence. The intervention also lowers installation prices. Randomized controlled trials based on the intervention show that selection into the program is important, whereas group pricing is not. Our results suggest that the program provided economies of scale and lowered consumer acquisition costs, leading to low-cost emission reductions. This paper was accepted by Matthew Shum, marketing.

Daylight Saving Time is argued to be effective in saving energy. Turkey is one of the few countries that annulled the clock changes and remained in the summertime zone in 2016. Therefore, the country provides a unique natural experiment to test and confirm this policy change. This paper studies the impact of clock changes on electric energy consumption and load shift. We use historical electrical energy consumption, electricity prices, and relevant atmospheric essential climate variables data in Turkey between 2012-2020. We adopt Multiple Linear Regression, Difference in Differences and Interrupted Time Series methodologies to analyse the historical data. This paper shows that the Daylight Saving Time policy does not lead to a measurable amount of electrical energy savings. Furthermore, it does not cause a noticeable continuous daily load shift throughout the year. We also claim that our findings should apply to countries such as the United States, India, Japan, Australia or China, and continents of Africa and South America, whose latitudes are between 42.0 degrees north and south of the equator. (C) 2021 The Authors. Published by Elsevier Ltd.

Objectives The study examines the variation in the daily incidence of eight acquisitive crimes: automobile theft, electromobile theft, motorcycle theft, bicycle theft, theft from automobiles, pickpocketing, residential burglary, and cyber-fraud before the lockdown and the duration of the lockdown for a medium-sized city in China. Methods Regression discontinuity in time (RDiT) models are used to test the effect of the lockdown measures on crime by examining the daily variation of raw counts and rate. Results It is indicated that in contrast to numerous violent crime categories such as domestic violence where findings have repeatedly found increases during the COVID-19 pandemic, acquisitive crimes in this city were reduced during the lockdown period for all categories, while “cyber-fraud” was found more resilient in the sense that its decrease was not as salient as for most other crime types, possibly due to people’s use of the internet during the lockdown period. Conclusions The findings provide further support to opportunity theories of crime that are contingent upon the need for a motivated offender to identify a suitable target in physical space.

Background Despite the benefits of physical activity (PA), the majority of Canadian youth are falling short of the recommended 60 min of moderate-to-vigorous physical activity (MVPA) per day. School-based physical activity programs such as intramurals, are important opportunities for youth to be physically active. There is limited evidence available on the impact of gender-specific (e.g., female-only, male-only) and co-ed intramurals on youth PA over time, however, evidence suggests female-only intramurals may be important for female MVPA. This research aims to capitalize on a natural experiment to generate practice-based evidence on the impact of changes in gender-specific and co-ed intramurals on youth MVPA over time. Methods This study used linked longitudinal school- and student-level data from Ontario secondary schools in year 5 (Y5:2016–2017), year 6 (Y6: 2017–2018) and year 7 (Y7: 2018–2019) of the COMPASS study. Data on intramurals from 55 schools were used to determine the changes to gender-specific and co-ed intramurals that occurred from Y5 to Y6. Baseline demographic characteristics were measured and data on PA and sport participation were collected in Y5, Y6 and Y7 on a sample of 4417 students. Hierarchical linear mixed regression models were used to estimate how changes in gender-specific and co-ed intramurals were associated with youth MVPA over time. Results Participation in intramural, varsity and community sport were all positively and significantly associated with youth MVPA. Changes in gender-specific and co-ed intramurals were not significantly associated with youth MVPA in Y6 or Y7. However, the positive association between maintaining the addition of gender-specific intramurals on female MVPA in Y7 was on par with the significance level of α = 0.05, suggesting that adding gender-specific intramurals may be important for female MVPA. Conclusions Adding gender-specific and co-ed intramurals may not be sufficient strategies to increase PA among youth. Further research should explore the effect of gender-specific intramurals on youth PA, as this study may have been underpowered at the school-level. Gender-specific intramurals may promote a supportive PA environment that promotes MVPA, especially among females. These intramurals may be an important component of more comprehensive strategies to increase youth MVPA.

The corporate social responsibility (CSR) report is an important carrier of non-financial information disclosure of enterprises and an important bridge of communication between enterprises and interested parties. Compulsory disclosure has promoted the improvement of CSR levels to some extent. While, for interested parties, their attention to various dimensions of CSR has significant differences, which leads to the heterogeneous impact of mandatory disclosure policy on its different dimensions. Through regression discontinuity design model (RDD), as well as using quasi-natural experiments of Chinese mandatory disclosure policies issued in 2008, we are going to get the following conclusions by analyzing the heterogeneous impact of mandatory disclosure on CSR with the environment (CER), social (SOC) and economic (ECO) three-dimension on the basis of verifying that mandatory disclosure policy has a positive impact on CSR. (1) The effects of mandatory disclosure on the three dimensions of CSR are heterogeneous, that is, the significant effects and directions are significantly different in the three dimensions. (2) The heterogeneity of mandatory disclosure on CSR is reflected in the changing trend, and there is no significant difference at the turning point of the trend. (3) The heterogeneity of the impact mechanism of mandatory disclosure on CSR is reflected in the different mediating variables of policy on different dimensions impact, that is, the mediating variables of CER and ECO are the environmental disclosure information and return on assets. (4) The impact of mandatory disclosure on different dimensions of CSR is heterogeneous when the nature of industries and property rights are different.

When institutions introduce financial aid policies, researchers have an opportunity to study these policies within the framework of a natural experiment. For this methodological note, I use a natural experiment that occurred at the public university when institutional scholarship for all first-time freshmen meeting a minimum high school grade point average and test score requirements was introduced. Scholarship renewal was contingent on credit hour accumulation and grade point averages while in college. I compare students with the same high school grades and test scores before and after the new policy implementation to evaluate the mechanisms of the associations among policy, loss of merit aid eligibility or failure to maintain grades or to accumulate credit hours, and retention. I suggest that mediation describes the association between the new policy and retention of high achieving in-state students. After the policy was implemented, these students were more likely to maintain their grades and full-time enrollment to remain scholarship eligible and, therefore, had greater return rates. Moderation helps to explain the association between merit aid and retention of out-of-state students. The effect of failure to maintain grades or full-time enrollment on departure was stronger for out-of-state students once financial aid was at stake. Limitations of inferring causation from natural experiments are discussed.

This study examines whether third party environmental disclosure affect green innovation at the firm-level. We find that environmental disclosure promotes Chinese companies to carry out green innov...

This paper uses the exogenous shock- Thailand military coup on May 22, 2014-as a natural experiment to test the impact of military political connections on the value of Thai’s listed firms. Results...

This paper exploits a natural experiment involving self-regulation in the ready-to-eat (RTE) breakfast cereal industry to evaluate how firms respond to entry in light of changes in competition and to estimate the value of brand equity as products are re-positioned. Self-regulation led to a crowding of the product space by forcing differentiated products to become more similar. Among other things we find that products constrained by regulation perform relatively worse than unconstrained products, brand equity specific to a product is tightly linked to existing product positions and does not transfer well to new positions, and that when competition increases, firms reposition to new segments and increase investments on product differentiation. The paper offers a performance based assessment of repositioning and to our knowledge offers the first empirical analysis in the strategy literature that measures in performance terms how repositioning changes the value of brand equity.

We use Texas's constitutional amendment in 1997 that expanded the scope of home equity loans as a source of exogenous variation to estimate the effects of relaxing credit constraints on small businesses. We find, using standard panel data methods and restricted-use micro-data from the US Census Bureau, that the Texas amendment increased the use of home equity finance by small businesses, increased new business and job creation and reduced establishment exit and job loss. The effects are larger and significant for businesses with fewer than ten employees.

Small firms dominated the American economy in the nineteenth century, and they still dominate in many developing economies today. This paper tests whether geographic market segmentation due to underdeveloped intracity transportation technology precludes the emergence of large retail/wholesale stores. I exploit the natural experiment of Boston’s rapid electrification from its previous horse-drawn streetcar system, which occurred between 1889 and 1896. Analyzing newly digitized data, I find that rail-connected locations experienced a sharp decline in the share of sole proprietorships among food retail/wholesale establishments after the electrification relative to off-rail locations. Changes in market access due to streetcar electrification can explain this effect. (JEL L25, L81, L92, N71, N91, R41)

In a large-scale natural experiment with over 14,000 individuals, we investigate whether public transport usage can be influenced by social norms and by economic incentives. Despite their effectiveness in other domains, we find a tightly estimated zero for descriptive social norms on ridership. Increasing the economic incentive, by doubling the trial period, significantly increases uptake and long-term usage. This increase is sustained for months after removing the incentive. The effect is mainly driven by initial low users, which is evidence for habit formation and highlights the heterogeneous effects of the policy. While there is scope for long-term behavior change, norm nudges might not be the most promising approach.

Background Substantial strategies to reduce clinical documentation were implemented by health care systems throughout the coronavirus disease-2019 (COVID-19) pandemic at national and local levels. This natural experiment provides an opportunity to study the impact of documentation reduction strategies on documentation burden among clinicians and other health professionals in the United States. Objectives The aim of this study was to assess clinicians' and other health care leaders' experiences with and perceptions of COVID-19 documentation reduction strategies and identify which implemented strategies should be prioritized and remain permanent post-pandemic. Methods We conducted a national survey of clinicians and health care leaders to understand COVID-19 documentation reduction strategies implemented during the pandemic using snowball sampling through professional networks, listservs, and social media. We developed and validated a 19-item survey leveraging existing post-COVID-19 policy and practice recommendations proposed by Sinsky and Linzer. Participants rated reduction strategies for impact on documentation burden on a scale of 0 to 100. Free-text responses were thematically analyzed. Results Of the 351 surveys initiated, 193 (55%) were complete. Most participants were informaticians and/or clinicians and worked for a health system or in academia. A majority experienced telehealth expansion (81.9%) during the pandemic, which participants also rated as highly impactful (60.1–61.5) and preferred that it remain (90.5%). Implemented at lower proportions, documenting only pertinent positives to reduce note bloat (66.1 ± 28.3), changing compliance rules and performance metrics to eliminate those without evidence of net benefit (65.7 ± 26.3), and electronic health record (EHR) optimization sprints (64.3 ± 26.9) received the highest impact scores compared with other strategies presented; support for these strategies widely ranged (49.7–63.7%). Conclusion The results of this survey suggest there are many perceived sources of and solutions for documentation burden. Within strategies, we found considerable support for telehealth, documenting pertinent positives, and changing compliance rules. We also found substantial variation in the experience of documentation burden among participants.

With the continuous expansion of the city scale and the continuous deepening of the innovation-driven concept, an innovative city pilot program, as a momentous spatial measure of the national innovation strategy, is of great significance for China's transformation to an innovative economy. Based on the Malmquist-Luenberger index, this paper estimates the ecological efficiency of 270 prefecture-level cities in China from 2005 to 2016. At the same time, the difference in differences (DID) method is applied to test the net effect of innovative city pilots on urban ecological efficiency, and the mediating effect model is used to analyze the transmission mechanism of innovative city pilots on ecological efficiency. The empirical results show that (1) innovative city construction is conducive to improving ecological efficiency. The validity of the conclusion is proven after a series of robustness tests, such as placebo test and propensity score matching and difference models (PSM-DID). (2) The heterogeneity analysis demonstrates that the pilot policy has a more significant effect on improving ecological efficiency in cities with higher education expenditure, science and technology investment and human capital. (3) The mechanism test results indicate that innovative city pilots can have a positive impact on urban ecological efficiency through technological innovation, adjusting the industrial structure and giving full play to the direct intervention effect of the government. Accordingly, this paper argues that the pilot scope of innovative cities can be further expanded. To promote the improvement of urban ecological efficiency, the circular accumulation of knowledge and technology and the construction of a green and innovative development atmosphere need to be considered.

This paper analyzes the long-term effects of potentially avoidable cesarean sections on children’s health. Using Finnish administrative data, we document that physicians perform more unplanned C-sections during their regular working hours on days that precede a weekend or public holiday and use this exogenous variation as an instrument for C-sections. We supplement our instrumental variables results with a differences-in-differences estimation strategy that exploits variation in birth mode within sibling pairs and across families. Our results suggest that avoidable unplanned C-sections increase the risk of asthma, but do not affect other immune-mediated disorders previously associated with C-sections.

We examine how executives' ability to control their firms' exposure to risk affects the design of their incentive-compensation contracts. Our natural experimental evidence shows that exchange-traded weather derivatives allow executives to control their firms' exposure to weather risk. Once these derivatives became available, those executives who use them to hedge experience relative reductions in their total compensation and equity incentives. The decline in compensation is consistent with a reduction in the risk premium that executives receive for exposure to weather risk. The decline in equity incentives is consistent with the relation between risk and incentives shifting in a complementary direction when executives can better control their firms' exposure to risk. Collectively, our findings provide evidence that executives' ability to control their firms' exposure and, by extension, their own to an important source of risk influences the design of their incentive-compensation contracts. JEL Classifications: G32; J33; J41.

Objectives to study the effect of psychological age on the risk of severe forms of Covid-19 in adults. Material and methods. Research method: natural experiment. The 1st measurement: indicators of biopsychological age - mid-2020, the 2nd measurement: assessment of Covid-19 disease - the end of 2020. Subjects: 239 people aged 35-70 (155 women). Methods for assessing psychological age, expected retirement age, biological age, and analysis of variance were used. Results. Indicators of the relative psychological age of an individual affect the development of the disease and its severity, while the combination of low indicators of psychological age with high biological indicators is most dangerous and increases the likelihood of developing severe forms of the disease.

In 2014, the city of Flint, MI, in the USA changed its public water source, resulting in severe water contamination and a public health crisis. Using the Flint water crisis as a natural experiment, we estimate the effect of in utero exposure to polluted water on health at birth. Matching vital statistics birth records with various sources of data, we use the synthetic control method to identify the causal impact of water pollution on key birth outcomes. Our results suggest that the crisis modestly increased the rate of low birth weight (LBW) by 1.8 percentage points (or 15.5%) but had little effect on the length of gestation or rate of prematurity. However, these effects are larger among children born to black mothers, as indicated by an increase in the rate of LBW by 2.5 percentage points (or 19%). Children born to white mothers exhibit, on average, a 30.1-g decrease in birth weight. We find little evidence that the male-to-female sex ratio declines in the overall population, suggesting that the in utero scarring effect of the Flint water crisis may dominate the channel of mortality selection. However, we observe a slight decline in the sex ratio among children born to black mothers. Finally, we find no notable change in the fertility rates of either black women or white women in Flint. These results are robust to a rich set of placebo and falsification tests.

We examine whether a firm’s voluntary disclosures, proxied by management earnings forecasts, affect its innovation activity. A firm making more disclosures generates fewer patents and lower-quantity patents. Enactment of SOX is applied as a natural experiment for an exogenous shock to voluntary disclosure. Corporate innovation is reduced for accelerated filers, especially after SOX becomes effective. Nondedicated institutional ownership, R&D spillover, and rival firms’ innovation are higher for accelerated filers after SOX. There is more of a negative effect of voluntary disclosure on innovation activity when product markets are highly competitive, industry information diffusion is speedy, and disclosures are more informative.

The coronavirus disease 2019 (COVID-19) pandemic caused a rapid shift to full-time remote work for many information workers. Viewing this shift as a natural experiment in which some workers were already working remotely before the pandemic enables us to separate the effects of firm-wide remote work from other pandemic-related confounding factors. Here, we use rich data on the emails, calendars, instant messages, video/audio calls and workweek hours of 61,182 US Microsoft employees over the first six months of 2020 to estimate the causal effects of firm-wide remote work on collaboration and communication. Our results show that firm-wide remote work caused the collaboration network of workers to become more static and siloed, with fewer bridges between disparate parts. Furthermore, there was a decrease in synchronous communication and an increase in asynchronous communication. Together, these effects may make it harder for employees to acquire and share new information across the network.

We examined the impact of primary care physician density on perinatal health outcomes in Norway. From 1992 and onwards, primary care physicians who chose to work in selected remote municipalities were given an annual reduction in their student loan. This reduction, combined with increased supply of physicians, led to an increase in the density of primary care physicians in these selected municipalities. Our register-based population study showed that this increase in physician density significantly improved perinatal health in terms of fewer fetal deaths and increased birth weight. The richness of the data allowed us to perform several robustness tests.

The formulation and implementation of Low-Carbon City Policy (LCCP) is an essential initiative for China to build its low-carbon society. Based on the panel data of 282 prefecture-level cities in China from 2003 to 2016, this study evaluates the effects of LCCP implementation on pilot cities’ carbon emission performance using difference-in-differences method, and then the mechanism has also been examined with a mediating effect model. The results show that: first, the LCCP implementation has increased the carbon emission performance of the pilot cities significantly, indicating that it is an effective way to promote the low-carbon transformation of Chinese cities. Second, the positive effects in CO2 performance resulting from LCCP demonstrate significant heterogeneity: in general, the cities in east China, with higher economic development level and in a larger size, achieve more significant CO2 emission reduction than their respective counterparts. The results on the mechanism test imply that the LCCP helps improve pilot cities’ carbon emission performance in three ways, including reducing energy consumption, updating the industrial structure, and promoting technological progress. Finally, some useful policy recommendations are put forward to promote China’s low-carbon city construction.

Augmented reality (AR)–based applications have been growing in prominence. Pokémon Go, one of the most popular AR game applications, has been engaging in strategic partnership with businesses. The game combines geospatial elements with gamification practices to incentivize user movement in the physical world. In this study, we examine the value of such strategic partnerships between Pokémon Go and associated businesses. Specifically, we use data of the online reviews for a firm to study consumer engagement and consumer perception after the release of the game on its associated businesses. We find that restaurants associated with Pokémon Go do indeed enjoy a higher level of consumer engagement and more positive consumer perception. We also find that characteristics of the business significantly moderate this impact overall. Using a parsimonious analytical model, we also demonstrate the mechanism behind these results. Our study provides insights into consumer economic behavior in the context of AR applications. We further inform the business owners and policymakers regarding the potential value of such strategic business partnerships with such applications.

PurposeCatastrophic supply chain disruptions can significantly damage the operational and financial performance of firms. While a growing body of literature on supply network structures has studied what influences supply networks' vulnerability to supply chain disruptions and capability to recover from them, it remains unclear how supply network structures change after major supply chain disruptions. We aim to provide an understanding of how these changes occur.Design/methodology/approachUsing a natural experiment approach and supply network data from Factset, this study investigates how firms' supply network structures change after experiencing the catastrophic supply chain disruptions caused by the 2011 Tohoku earthquake and tsunami in Japan. We capture post-earthquake supply network changes using the measures of degree centrality and ego network density.FindingsThe results of the analysis suggest that compared to unaffected firms, the affected firms experience changes in their supply network structures tending toward lower complexity measured by in-degree centrality, out-degree centrality and ego network density.Originality/valueThis study contributes to social network theory and the complex adaptive supply network literature by providing empirical evidence of structural changes in supply networks after catastrophic supply chain disruptions. A managerial contribution is made by providing a reflection on why these changes might be occurring and alert firms to the challenges of managing complexity in their supply networks.

We utilize the implementation of the 1986 Compulsory Education Law in China as a natural experiment to examine the relationship between educational attainment and migrant entrepreneurship. Using data from the 2017 China Migrants Dynamics Survey, results from our preferred two-stage least square model, which uses instrumental variable and difference-in-differences estimators to correct for endogeneity, suggest that having one additional year of education generates a 3.5 percentage points increase in the probability of being an employer entrepreneur vis-a-vis an employee, and a 4.7 percentage points increase in the probability of being an employer entrepreneur vis-a-vis a solo entrepreneur. Having better education, however, does not affect the propensity to become an entrepreneur in general vis-a-vis an employee or a solo entrepreneur vis-a-vis an employee. These results are robust to various checks including alternative estimation methods and ways of defining entrepreneurship. We also explore the channels through which educational attainment influences whether one chooses to become an employer entrepreneur. Our findings suggest that assortative mating, difficulties experienced in the host location, permanent settlement intention and social capital mediate the relationship between better education and the choice of both becoming an employer entrepreneur vis-a-vis a solo entrepreneur and an employer entrepreneur vis-a-vis an employee, while risk preferences are a mechanism through which education affects the probability of becoming an employer entrepreneur as opposed to a solo entrepreneur.

The wild success of a few online community-produced knowledge goods, notably Wikipedia, has obscured the fact that most attempts at forming online communities fail. A large body of work analyses motivations behind user contributions to successful, online communities but less is known, however, about early-stage interventions that might make online communities more or less successful. This study evaluates information seeding, a popular practice to bootstrap online communities by enabling contributors to build on externally-sourced information rather that starting from scratch. I analyze the effects of information seeding on follow-on contributions using data from more than 350 million contributions made by over 577,000 contributors to OpenStreetMap, a Wikipedia-style digital map-making community that was seeded with data from the US Census. To estimate the effects of information seeding, I rely on a natural experiment in which an oversight caused about 60% of quasi-randomly chosen US counties to be seeded with a complete Census map, while the rest were seeded with less complete versions. While access to knowledge generally encourages follow-on knowledge production, I find that a higher level of information seeding significantly lowered follow-on knowledge production and contributor activity on OpenStreetMap and was also associated with lower levels of long-term quality. I argue that information seeding can crowd out contributors’ ability to develop ownership over baseline knowledge and disincentivize follow-on contributions in some circumstances. Empirical evidence supports this explanation as the mechanism through which a higher level of information seeding can stifle rather than spur knowledge production in online communities.

The maternity benefit scheme piloted as Indira Gandhi Matritva Sahyog Yojana (IGMSY) since 2011 and recently rolled out as Pradhan Mantri Matru Vandana Yojana (PMMVY) incentivizes mothers to participate in infant health-promoting activities. It has become India's largest conditional cash transfer program ever, outrivaling the country's first-generation maternity benefit scheme Janani Suraksha Yojana (JSY), which incentivizes institutional delivery and has been criticized for its unintended side effects on fertility. We approach IGMSY's geographically targeted pilot phase as a natural experiment and use data from a large national health survey to estimate its effects by a matched-pair difference-in-differences approach. Consistent with the program's conditions, we find increases in infant immunization. As side effect, long-term utilization of public health facilities becomes more frequent and intervals between eligible births increase by 17%. Our findings suggest that India'ns second-generation maternity benefit scheme has been more carefully designed than its predecessor, with side effects that support the program's broader objectives. But both direct and indirect effects are small and can make only a small contribution to redressing India's dismal maternal and child health record.

This paper provides evidence on the impact of European Banking Union (BU) and the associated Single Supervisory Mechanism (SSM) on the risk disclosure practices of European banks. The onset of BU and the associated rules are considered as an exogenous shock that provides the setting for a natural experiment to analyze the effects of the new supervisory arrangements on bank risk disclosure practices. A Difference-in-Differences approach is adopted, building evidence from the disclosure practices of systemically important banks supervised by the European Central Bank (ECB) and other banks supervised by national regulators over the period 2012–2017. The main findings are that bank risk disclosure increased overall following BU but there was a weakening of disclosure by SSM-supervised banks relative to banks supervised by national authorities. We also find that the overall positive effect of the BU on bank disclosure is stronger for less profitable banks and in the most troubled economies of the Eurozone (GIPSI countries), while the negative effect on centrally supervised banks is stronger if bank CEOs act also as chairmen (CEO duality). We interpret these findings in light of the fact that the new institutional arrangements for bank supervision under which the ECB relies on local supervisors to collect the information necessary to act gives rise to inefficiencies with respect to the speed and completeness of the information flow between SSM supervised banks and the ECB, which are reflected in bank disclosure practices.

This paper examines the relation between crowd support and home advantage in men’s professional football in making use of a unique “natural experiment” induced by restrictions due to the COVID-19 pandemic: the so-called ghost games in the top three German football divisions at the end of the 2019/2020 season. We find that there is a reduced home advantage in the first division, whereas no change is observed in the second and third divisions. Our regression analysis indicates that the decrease in the home advantage and the heterogeneity across divisions are not sensitive to a variety of performance, location, and team covariates and are best explained through the lower occupancy rate in the stadia. Hence, the decrease in occupancy to zero at the ghost games has been less dramatic for teams that have been used to low occupancy rates. We cannot find strong evidence for a change in referee behavior or teams’ tactics as main impact channels of occupancy rates on the home advantage. Hence, we argue that psychological reasons are of higher importance.

Enterprises are the market players for carbon reductions and carbon trading, and they are also the significant driving force in a low-carbon economy and society. Using the data of A-share listed companies from 2010 to 2016, this study uses a difference-in-differences (DID) model to examine the effects of the low-carbon city construction on corporate carbon reduction performance. Consistent with our hypotheses, we find that the low-carbon city construction promotes corporate carbon reduction performance. Further analysis indicates that the policy effect is stronger for state-owned enterprises (SOEs) than non-state-owned enterprises (non-SOEs). Moreover, environmental quality can affect the promotion of local government officials, which is more prominent in pilot low-carbon cities, and political promotion incentives significantly improve corporate carbon reduction performance. Furthermore, the highest emission reduction effects come in the fourth year after adopting a carbon reduction policy and are concentrated among the firms in the eastern region. Overall, our findings offer a new point view for a deeper understanding of the improvement of corporate carbon reduction performance, and provide microscopic evidence for the objective evaluation of the environmental effects of China's low-carbon city pilot policies.