Natural Experiment Research Articles

Adults in the room? The auditor and dividends in small firms: evidence from a natural experiment

Adults in the room? The auditor and dividends in small firms: evidence from a natural experiment

The impact of the world’s first regulatory, multi-setting intervention on sedentary behaviour among children and adolescents (ENERGISE): a natural experiment evaluation

BackgroundRegulatory actions are increasingly used to tackle issues such as excessive alcohol or sugar intake, but such actions to reduce sedentary behaviour remain scarce. World Health Organization (WHO) guidelines on sedentary behaviour call for system-wide policies. The Chinese government introduced the world’s first nation-wide multi-setting regulation on multiple types of sedentary behaviour in children and adolescents in July 2021. This regulation restricts when (and for how long) online gaming businesses can provide access to pupils; the amount of homework teachers can assign to pupils according to their year groups; and when tutoring businesses can provide lessons to pupils. We evaluated the effect of this regulation on sedentary behaviour safeguarding pupils.MethodsWith a natural experiment evaluation design, we used representative surveillance data from 9- to 18-year-old pupils before and after the introduction of the regulation, for longitudinal (n = 7,054, matched individuals, primary analysis) and repeated cross-sectional (n = 99,947, exploratory analysis) analyses. We analysed pre-post differences for self-reported sedentary behaviour outcomes (total sedentary behaviour time, screen viewing time, electronic device use time, homework time, and out-of-campus learning time) using multilevel models, and explored differences by sex, education stage, residency, and baseline weight status.ResultsLongitudinal analyses indicated that pupils had reduced their mean total daily sedentary behaviour time by 13.8% (95% confidence interval [CI]: -15.9 to -11.7%, approximately 46 min) and were 1.20 times as likely to meet international daily screen time recommendations (95% CI: 1.01 to 1.32) one month after the introduction of the regulation compared to the reference group (before its introduction). They were on average 2.79 times as likely to meet the regulatory requirement on homework time (95% CI: 2.47 to 3.14) than the reference group and reduced their daily total screen-viewing time by 6.4% (95% CI: -9.6 to -3.3%, approximately 10 min). The positive effects were more pronounced among high-risk groups (secondary school and urban pupils who generally spend more time in sedentary behaviour) than in low-risk groups (primary school and rural pupils who generally spend less time in sedentary behaviour). The exploratory analyses showed comparable findings.ConclusionsThis regulatory intervention has been effective in reducing total and specific types of sedentary behaviour among Chinese children and adolescents, with the potential to reduce health inequalities. International researchers and policy makers may explore the feasibility and acceptability of implementing regulatory interventions on sedentary behaviour elsewhere.

Impact of the First-Wave COVID-19 Pandemic on Medical Expenditure for Older Adults in China: Lessons from a Natural Experiment

ABSTRACT Older adults’ access to healthcare services may have been affected by the COVID-19 pandemic. This study explored the effect of the first wave pandemic on the medical expenditure of older adults in China. Difference-in-Difference models captured both temporal and geographical variation in COVID-19 exposure to estimate the impacts of the pandemic on medical expenditure through a quasi-natural experiment. Data derived from the China Family Panel Studies. Results indicate that exposure to the pandemic significantly decreased total medical expenditures, hospital expenditures, and non-hospital medical expenditures of Chinese older adults by 15% (95% CI 12%–17%), 5% (95% CI 2%–7%), and 15% (95% CI 13%–16%), respectively, for each standardized severity increment. Females, less well-educated people, and individuals without internet access were most susceptible to experiencing these reductions. This study revealed that COVID-19 exerted a detrimental influence on the medical expenditure of older adults in mainland China. The “hidden epidemic” of non-COVID-19 medical needs of older adults deserves more attention on the part of policymakers.

Green credit policies and heavily polluting enterprises’ maturity mismatch between investment and financing: a difference-in-differences approach

ABSTRACT Taking the Green Credit Guidelines as a natural experiment, we explore the effect of green credit policies on heavily polluting enterprises’ maturity mismatch between investment and financing using the difference-in-differences method. We investigate the influencing mechanism of green credit policies on heavily polluting enterprises’ maturity mismatch in investment and financing from the new perspective of overinvestment. We find that green credit policies alleviate heavily polluting enterprises’ maturity mismatch between investment and financing by inhibiting overinvestment. In addition, we find that the effect of green credit policies on the maturity mismatch between investment and financing is more significant for the enterprises in the cities with higher digital financial inclusion, higher corporate social responsibility, and higher green innovation. Further, we find that green credit policies can help promote heavily polluting enterprises to increase green investment.

Risk compensation after COVID-19 vaccination: Evidence from vaccine rollout by exact birth date in South Korea.

We utilize the phased rollout of COVID-19 vaccines by exact birth date in South Korea as a natural experiment for testing risk compensation. People may resume face-to-face social activities following vaccination because they perceive lower risk of infection. Applying a regression discontinuity design based on birth date cutoffs for vaccine eligibility, we find no evidence of risk-compensating behaviors, as measured by large, high-frequency data from credit card and airline companies as well as survey data. We find some evidence of self-selection into vaccine take-up based on perception toward vaccine effectiveness and side effects, but the treatment effects do not differ between compliers and never-takers.

Exploring the Impact of Campus Landscape Visual Elements Combination on Short-Term Stress Relief among College Students: A Case from China

Although the effect of campus landscape space on stress relief among college students has been confirmed, few existing studies have considered the impact on stress recovery from the perspective of factor combination, and the key visual elements and the most effective combination of visual elements to relieve stress are still unclear. This study attempts to conduct a natural experiment within Chinese campuses, measuring physiological indicators of stress such as heart rate (HR), frequency domain index of heart rate variability (LF/HF), skin conductance level (SCL), skin temperature (SKT), and respiratory rate (RESP) using physiological instruments. It explored the effects of visual elements and their combinations in campus landscape spaces on short-term stress relief among college students through semantic segmentation, multifactorial analysis of variance, and post hoc multiple comparison methods. Research results demonstrate that the presence of water elements in the field of vision can effectively improve the stress relief effects of landscape spaces. Reasonable combinations of natural landscape elements and artificial landscape elements in the design can also effectively promote stress relief among students. Building facade area and sky area, water area and sky area, and plant species and pavement area are three combinations of factors with the strongest interactive effects. “Natural water scenery” and “exquisite artificial” are two campus landscape design patterns most conducive to short-term stress relief.

THE PROBLEM OF REGULATING FUNGICIDES ON THE SKIN SURFACE FOR OCCUPATIONAL SKIN DISEASE IN AGRICULTURAL WORKERS’ RISK PREDICTION

The aim. To establish the norms of fungicides on the skin surface and predicting the risk of occupational skin pathology in agricultural workers to develop measures to prevent diseases caused by dermal exposure to pesticides. Materials and methods. The natural experiment was performed in accordance with modern requirements (European Food Safety Authority (2022), and the risk assessment was carried out according to the Recommendations (Approved by the Ministry of Health of Ukraine No. 324 issued on 13.05.2009) with different methods of spraying techniques: rod, air blast fan spraying, pre-sowing, aviation, knapsack treatment. 17 series of natural experiments were performed, and the air of the working zone area (n =56) and dermal exposure (n =56) were analyzed for each worker with different pesticide application methods. Quantitative determination of pesticide content was carried out by gas-liquid and high-performance liquid chromatography methods. The results were statistically processed using a package of licensed statistical programs MedStat v.5.2 (Copyright © 2003-2019) and Microsoft® Excel® for Microsoft 365 MSO. Results. It was established that there is pesticide contamination, mainly of the gloves of tank filling operators when preparing working solutions. No contamination of the skin surface was detected; only pesticide residues were present on the surface of the workers’ overalls. A comparison of the exposure dose in case of percutaneous exposure during the performance of technological operations with different methods of processing, dermal equivalents of Acceptable Operator Exposure Level of pesticide to workers’ skin (DE AOEL) and the allowable dermal dose for professional contingents (ADderm) and the hazard coefficients by dermal exposure (HCderm) showed that that dermal exposure during individual technological operations with different processing methods had a reliable difference between processing methods, but there is no difference within one application method. Conclusions. During the comparison of the hazard coefficients for dermal exposure, calculated according to different models, no significant difference was found between the risks calculated according to DE AOEL and ADderm for individual technological operations in various treatment methods, except for the operator who performed knapsack treatment and the risk calculated according to ADderm is significantly lower compared to the DE AOEL risk.

Effect of 20 mph speed limits on traffic injuries in Edinburgh, UK: a natural experiment and modelling study

IntroductionThere is limited research evaluating 20 mph speed limit interventions, and long-term assessments are seldom conducted either globally or within the UK. This study evaluated the impact of the phased...

Interpersonal Fundraising Methods Are Associated With Lower Donation Value Over Time

Charities have invited public scorn through their use of chugging (or “charity mugging”) methods of fundraising, which involve interpersonal interaction between fundraisers and potential donors. It is not known how such mass market interpersonal fundraising methods are associated with donors giving over time. We analyzed transactional data from a natural experiment involving 213,404 donors to 45 charities to examine the relationship between interpersonal interaction at the time of donor recruitment and the long-term value of donations made by those donors. Multilevel analyses show that different fundraising methods are associated with different donation values. Specifically, mass market fundraising methods that involve interpersonal interaction are linked to lower donation values over time (β = −.12; equating to 59% fewer dollars donated on average in the second year), driven by much higher rates of cancelation (odds ratio [OR] = 3.14). We theorize several possible mechanisms through which interpersonal fundraising comes to generate these poorer outcomes.

Regulatory lag, efficiency, and performance. Lessons from a case study

Our main contribution is to identify the risks implied by the existence of prolonged regulatory lags. We hypothesize that a likely first response is to reduce OPEX, increasing efficiency. If the lag persists for enough time, a vicious circle of inefficiency, disinvestment, and reduced performance can follow. We use a regulatory episode affecting natural gas distributors in Argentina as a natural experiment, controlling with other Latin American countries’ utilities not exposed to the same regulatory stimuli. We evaluate the relative efficiency of fourteen firms for five countries, in seven years, using Stochastic Frontiers Analysis (SFA). Thus, we perform a regulatory impact analysis (RIA) to assess the consequences on the performance of two idiosyncratic regulatory policy instruments applied in the distribution gas industry in Argentina in the 1998–2021 period (the 2002 Public Emergency Law and the 2016 Integral Tariff Review).

The effect of internal control quality and internal control disclosure regulation on executive perks: A quasi natural experiment from China

This paper investigates the effect of internal control quality and mandatory internal control disclosure regulation on executive perks in China. Based on a sample of Chinese firms between 2008 and 2019, this study finds that internal control quality and the mandatory disclosure regulation limit both under‐consumption and over‐consumption of executive perks. Furthermore, the mandatory regulation strengthens the relationship between internal control quality and the levels of executive perks. The results are consistent across alternative measures of key variables and are robust to endogeneity analyses. The findings of this study have important implications for policymakers, managers, and investors seeking to understand the determinants of the abnormal consumption of executive perks and the associated economic consequences of the internal control system.

The impact of environmental regulation on firms’ markups: evidence from China

ABSTRACT A comprehensive evaluation of the costs and benefits of environmental regulations provides empirical evidence for policymakers to formulate and introduce environmental policies. Firms’ profitability and competitiveness manifest their market power and provide the micro foundation for economic development and social stability. Therefore, this paper focus on investigating the impact of air pollution environmental regulation on manufacturing firms’ market power, measured by markups, with a difference-in-differences (DID) method. Using air pollution control policy, requiring China’s Key Cities for Air Pollution Control (KCAPC) to meet air quality standards within a specified time limit as a natural experiment, our DID estimations show that air pollution regulation significantly leads to an increase in firms’ markup rate by 0.002 in key cities that did not meet air quality standards. Heterogeneous effects show that this impact is larger for polluting firms, private-owned and foreign-owned firms, and firms located in western and central cities and cities with high marketization. Productivity and market share may be two main influencing channels to explain the positive impact of air pollution environmental regulation on firms’ markups. Our findings suggest that strengthening environmental regulation is conducive to improving the competitiveness and market power of manufacturing firms, lending support to the enforcement of environmental regulations.

Complex patterns of morphological diversity across multiple populations of an urban bird species.

Urbanization presents a natural evolutionary experiment because selection pressures in cities can be strongly mismatched with those found in species' historic habitats. However, some species have managed to adapt and even thrive in these novel conditions. When a species persists across multiple cities, a fundamental question arises: do we see similar traits evolve under similar novel environments? By testing if and how similar phenotypes emerge across multiple urban populations, we can begin to assess the predictability of population response to anthropogenic change. Here, we examine variation within and across multiple populations of a songbird, the dark-eyed junco (Junco hyemalis). We measured morphological variations in juncos across urban and non-urban populations in Southern California. We investigated whether the variations we observed are due to differences in environmental conditions across cities. Bill shape differed across urban populations; Los Angeles and Santa Barbara juncos had shorter, deeper bills than non-urban juncos, but San Diego juncos did not. On the other hand, wing length decreased with the built environment, regardless of the population. Southern Californian urban juncos exhibit both similarities and differences in morphological traits. Studying multiple urban populations can help us determine the predictability of phenotypic evolutionary response to novel environments.

Digitalization and Retirement Contribution Behavior: Evidence from Administrative Data

Abstract Retirement savings decisions are increasingly mediated by digital technologies that promise to help individuals plan adequately for their retirement. We exploit a natural experiment to show that introducing a digital pension application increases the probability of making a voluntary retirement contribution by 1.8 percentage points, from an average pretreatment contribution rate of 2.8%. Men and higher-income earners are more likely to respond to the app introduction. We then leverage a field experiment to show that using the app affects contribution behavior mainly through reducing the “hassle” costs of making contributions, rather than by providing information on the associated tax savings. (JEL C93, D14, D83, G51)

Variety-Based Congestion in Online Markets: Evidence from Mobile Apps

In many online markets, consumers have to spend time and effort browsing through products. The addition of new products could make other products less visible, creating congestion externalities. Using Android app store data, I take advantage of a natural experiment—a redesign of part of the store—to show evidence of congestion externalities online: more apps in the market directly reduce per app usage/downloads. The natural experiment also increases long-run entry, but a structural demand model that accounts for congestion externalities suggests that 40 percent of consumer variety welfare gains are lost from higher congestion. (JEL D12, D22, D62, L86)

Exploring viral infections' role in Kawasaki disease onset: A study during the COVID-19 pandemic.

During thecoronavirus disease 2019 (COVID-19) pandemic, known viral diseases declined in all ages. By using the current situation as a natural experiment, this study aimed to evaluate whether the change in the incidence of Kawasaki disease (KD) during the COVID-19 pandemic varies with age and whether a specific infectious disease mediates the occurrence of KD. Monthly number of KD patients were extracted from the nationwide inpatient database. Segmented regression analysis was conducted on the interrupted time series data. Additionally, causal mediation analysis was performed to examine the role of viral infections in the changes in the number of KD patients. After the first emergency declaration for COVID-19 in Japan, there was an immediate decrease in the number of KD patients per 100 000 population aged between 6 months and 4 years (immediate change = -2.66; 95% confidence interval [CI]: -5.16 to -0.16) and aged 5-15 years (immediate change = -0.26; 95% CI: -0.49 to -0.04). However, no immediate change was observed in patients under 6 months of age. In the causal mediation analysis for each viral infection, it was found that the decrease in the number of patients with KD was mediated by changes in the number of patients with pharyngoconjunctival fever and infectious gastroenteritis. The current results suggest that viral infections may be one of the etiological agents for KD, while they may not be the main cause in early infancy. Specifically, we found that adenovirus infection and gastroenteritis was closely related to the onset of KD in some areas of Japan.

Social influence and the choice of product upgrades: evidence from virtual product adoption in online games

PurposePrevious studies on social influence and virtual product adoption have mainly taken users’ purchase behavior as a dichotomous variable (i.e. purchasing or not). Given the prevalence of competing versions (basic vs upgraded) of a virtual product in online communities, this paper investigated the differences in the effect of social influence on users’ adoption of basic and upgraded choices of a virtual product. It also examined how the effect varies with users’ social status and user-level network density.Design/methodology/approachA natural experiment was conducted in an online game community. Two competing versions (basic vs upgraded) of a virtual product were provided for in-game purchase while a random set of users selected from 897,765 players received the notification of their friends’ adoption information. A competing-risk model was used to test the hypotheses.FindingsSocial influence exerts a stronger positive effect on users’ adoption of the upgraded virtual product than of the basic virtual product. Middle-status users have the greatest (least) susceptibility to social influence in adopting the upgraded (basic) virtual product than low- and high-status users. User’s network density enhances the effect of social influence on adoption of both virtual products, even more for the upgraded one.Originality/valueThis research contributes to the social influence and product adoption literature by disentangling the different effects of social influence on basic and upgraded versions of a virtual product. It also identifies the boundary conditions that social influence works for each version of the virtual product.

Does maternity leave reform impact on the labour supply of the elderly? Evidence from a natural experiment in Vietnam

AbstractThe aging population has been rising rapidly in every country, slowing the labour force and causing lower per capita growth. Many policies incentivize working in old age as it can alleviate the challenges of the aging population. This study examines the impacts of the extended maternity leave reform in Vietnam on elderly labour market outcomes. As grandparents' childcare responsibility may be reduced by maternal childcare following the extended maternal leave, especially for elderly living with children smaller than 1 year old, the reform gives older adults or grandparents more flexibility to join the labour market. Using the difference‐in‐differences model, we find that older people in the treatment group are more likely to return to the labour market following the reform implementation. The effect is positive and most robust for the self‐employment group rather than waged employment and for males rather than females. Our study suggests that there is a need for a policy design to shift public finance into the healthcare and pension system.

Do minority shareholder protection laws benefit investors? Evidence from a natural experiment on cross-listed firms

Do minority shareholder protection laws benefit investors? Evidence from a natural experiment on cross-listed firms

Histologic, metabolomic, and transcriptomic differences in fir trees from a peri-urban forest under chronic ozone exposure.

Urbanization modifies ecosystem conditions and evolutionary processes. This includes air pollution, mostly as tropospheric ozone (O3), which contributes to the decline of urban and peri-urban forests. A notable case are fir (Abies religiosa) forests in the peripheral mountains southwest of Mexico City, which have been severely affected by O3 pollution since the 1970s. Interestingly, some young individuals exhibiting minimal O3-related damage have been observed within a zone of significant O3 exposure. Using this setting as a natural experiment, we compared asymptomatic and symptomatic individuals of similar age (≤15 years old; n = 10) using histologic, metabolomic, and transcriptomic approaches. Plants were sampled during days of high (170 ppb) and moderate (87 ppb) O3 concentration. Given that there have been reforestation efforts in the region, with plants from different source populations, we first confirmed that all analyzed individuals clustered within the local genetic group when compared to a species-wide panel (Admixture analysis with ~1.5K SNPs). We observed thicker epidermis and more collapsed cells in the palisade parenchyma of needles from symptomatic individuals than from their asymptomatic counterparts, with differences increasing with needle age. Furthermore, symptomatic individuals exhibited lower concentrations of various terpenes (ß-pinene, ß-caryophylene oxide, α-caryophylene, and ß-α-cubebene) than asymptomatic trees, as evidenced through GC-MS. Finally, transcriptomic analyses revealed differential expression for 13 genes related to carbohydrate metabolism, plant defense, and gene regulation. Our results indicate a rapid and contrasting phenotypic response among trees, likely influenced by standing genetic variation and/or plastic mechanisms. They open the door to future evolutionary studies for understanding how O3 tolerance develops in urban environments, and how this knowledge could contribute to forest restoration.