Showing papers on "Natural experiment published in 2020"

The Immediate Effect of COVID-19 Policies on Social Distancing Behavior in the United States

Abstract: Anecdotal evidence points to the effectiveness of COVID-19 social distancing policies, however, their effectiveness vis-a-vis what is driven by public awareness and voluntary actions have not been studied. Policy variations across US states create a natural experiment to study the causal impact of each policy. Using a difference-in-differences methodology, location-based mobility, and daily state-level data on COVID-19 tests and confirmed cases, we rank policies based on their effectiveness. We show that statewide stay-at-home orders had the strongest causal impact on reducing social interactions. In contrast, most of the expected impact of more lenient policies were already reaped from non-policy mechanisms. Moreover, stay-at-home policy results in a steady decline in confirmed cases, starting from ten days after implementation and reaching a 37% decrease after fifteen days, consistent with the testing practices and incubation period of the disease.

Natural experiments in leadership research: An introduction, review, and guidelines

Abstract: Endogeneity is a serious challenge for leadership research. To overcome the problem, researchers increasingly rely upon experimental designs, such as laboratory and field experiments. In this paper, we argue that natural experiments — in the form of standard natural experiments, instrumental variable, and regression discontinuity designs — offer additional opportunities to infer causal relationships. We conduct a systematic, cross-disciplinary review of 87 studies that leverage natural experimental designs to inquire into a leadership topic. We introduce the standard natural experiment, instrumental variable, and regression discontinuity design and use topic modeling to analyze which leadership topics have been investigated using natural experimental designs. Based on the review, we provide guidelines that we hope will assist scholars in discovering natural exogenous variations, selecting the most suitable form of natural experiment and by mobilizing appropriate statistical techniques and robustness checks. The paper is addressed to leadership and management scholars who aim to use natural experiments to infer causal relationships.

The Immediate Effect of COVID-19 Policies on Social Distancing Behavior in the United States

Abstract: Anecdotal evidences point to effectiveness of COVID-19 social distancing policies, however, their effectiveness vis-a-vis what is driven by public awareness and voluntary actions have not been studied. Policy variations across US states create a natural experiment to study the causal impact of each policy. Using a difference-in-differences methodology, location-based mobility, and daily state-level data on COVID-19 tests and confirmed cases, we rank policies based on their effectiveness. We show that statewide stay-at-home orders had the strongest causal impact on reducing social interactions. In contrast, most of the expected impact of more lenient policies were already reaped from nonpolicy mechanisms. Moreover, stay-at-home policy results in a steady decline in confirmed cases, starting from ten days after implementation and reaching a 37% decrease after fifteen days, consistent with the testing practices and incubation period of the disease.

Conceptualising Natural and Quasi Experiments in Public Health

Abstract: Background: Natural or quasi experiments are appealing for public health research because they enable the evaluation of events or interventions that are difficult or impossible to manipulate experimentally, such as many policy and health system reforms. However, there remains ambiguity in the literature about their definition and how they differ from randomised controlled experiments and from other observational designs. Methods: We conceptualise natural experiments in in the context of public health evaluations, align the study design to the Target Trial Framework, and provide recommendation for improvement of their design and reporting. Results: Natural experiment studies combine features of experiments and non-experiments. They differ from RCTs in that exposure allocation is not controlled by researchers while they differ from other observational designs in that they evaluate the impact of event or exposure changes. As a result they are, in theory, less susceptible to bias than other observational study designs. Importantly, the strength of causal inferences relies on the plausibility that the exposure allocation can be considered "as-if randomised". The target trial framework provides a systematic basis for assessing the plausibility of such claims, and enables a structured method for assessing other design elements. Conclusions: Natural experiment studies should be considered a distinct study design rather than a set of tools for analyses of non-randomised interventions. Alignment of natural experiments to the Target Trial framework will clarify the strength of evidence underpinning claims about the effectiveness of public health interventions.

When Consumption Regulations Backfire: The Role of Political Ideology:

Abstract: The authors investigate the role of political ideology in consumer reactions to consumption regulations. First, they demonstrate via a natural experiment that conservatives (but not liberals) incre...

Using natural experiments to improve public health evidence: a review of context and utility for obesity prevention.

Abstract: Natural experiments are increasingly valued as a way to assess the health impact of health and non-health interventions when planned controlled experimental research designs may be infeasible or inappropriate to implement. This study sought to investigate the value of natural experiments by exploring how they have been used in practice. The study focused on obesity prevention research as one complex programme area for applying natural experiment studies. A literature search sought obesity prevention research from January 1997 to December 2017 and identified 46 population health studies that self-described as a natural experiment. The majority of studies identified were published in the last 5 years, illustrating a more recent adoption of such opportunities. The majority of studies were evaluations of the impact of policies (n = 19), such as assessing changes to food labelling, food advertising or taxation on diet and obesity outcomes, or were built environment interventions (n = 17), such as the impact of built infrastructure on physical activity or access to healthy food. Research designs included quasi-experimental, pre-experimental and non-experimental methods. Few studies applied rigorous research designs to establish stronger causal inference, such as multiple pre/post measures, time series designs or comparison of change against an unexposed group. In general, researchers employed techniques to enhance the study utility but often were limited in the use of more rigorous study designs by ethical considerations and/or the particular context of the intervention. Greater recognition of the utility and versatility of natural experiments in generating evidence for complex health issues like obesity prevention is needed. This review suggests that natural experiments may be underutilised as an approach for providing evidence of the effects of interventions, particularly for evaluating health outcomes of interventions when unexpected opportunities to gather evidence arise.

Reusing Natural Experiments

Abstract: After a natural experiment is first used, other researchers often reuse the setting, examining different outcome variables. We use simulations based on real data to illustrate the multiple hypothesis testing problem that arises when researchers reuse natural experiments. We then provide guidance for future inference based on popular empirical settings including difference-in-differences regressions, instrumental variables regressions, and regression discontinuity designs. When we apply our guidance to two extensively studied natural experiments, business combination laws and the Regulation SHO pilot, we find that many results that were statistically significant using single hypothesis testing do not survive corrections for multiple hypothesis testing.

Natural Experiments

Abstract: The term natural experiment is used inconsistently. In one interpretation, it refers to an experiment where a treatment is randomly assigned by someone other than the researcher. In another interpretation, it refers to a study in which there is no controlled random assignment, but treatment is assigned by some external factor in a way that loosely resembles a randomized experiment---often described as an "as if random" assignment. In yet another interpretation, it refers to any non-randomized study that compares a treatment to a control group, without any specific requirements on how the treatment is assigned. I introduce an alternative definition that seeks to clarify the integral features of natural experiments and at the same time distinguish them from randomized controlled experiments. I define a natural experiment as a research study where the treatment assignment mechanism (i) is neither designed nor implemented by the researcher, (ii) is unknown to the researcher, and (iii) is probabilistic by virtue of depending on an external factor. The main message of this definition is that the difference between a randomized controlled experiment and a natural experiment is not a matter of degree, but of essence, and thus conceptualizing a natural experiment as a research design akin to a randomized experiment is neither rigorous nor a useful guide to empirical analysis. Using my alternative definition, I discuss how a natural experiment differs from a traditional observational study, and offer practical recommendations for researchers who wish to use natural experiments to study causal effects.

No extension without representation? Evidence from a natural experiment in collective bargaining

Abstract: In many countries, collective bargaining coverage is enhanced by government-issued extensions that widen the reach of collective agreements beyond their signatory parties to all firms and workers in the sector. This paper analyzes the causal impact of extensions using a natural experiment in Portugal that resulted in a sharp and unanticipated decline in the extension probability of agreements. Our results, based on a regression discontinuity design, indicate that extensions had a negative impact on employment growth. This effect is concentrated among nonaffiliated firms, which may reflect the limited representativeness of employer associations.

Returns to Low-Skilled International Migration : Evidence from the Bangladesh-Malaysia Migration Lottery Program

Abstract: Many economists believe that the returns to migration are high. However, credible experimental estimates of the benefits of migration are rare, particularly for low-skilled international migrants and their families. This paper studies a natural experiment in Bangladesh, where low-skilled male migrant workers to Malaysia were selected via a large-scale lottery program. This study tracked the households of lottery applicants and surveyed 3,512 lottery winners and losers. Five years after the lottery, 76 percent of the winners had migrated internationally compared with only 19 percent of the lottery losers. Using the lottery outcome as an instrument, the paper finds that the government intermediated migration increased the incomes of migrants by over 200 percent and their household per capita consumption by 22 percent. Furthermore, low-skilled international migration leads to large improvements in a wide array of household socioeconomic outcomes, including female involvement in key household decisions. Such large gains arise, at least in part, due to lower costs of government intermediation.

When Time Is of the Essence: A Natural Experiment on How Time Constraints Influence Elections

Abstract: Foundational theories of voter turnout suggest that time is a key input in the voting decision, but we possess little causal evidence about how this resource affects electoral behavior. In this art...

Social Preferences and Economic Decision-Making in the Wake of COVID-19: Experimental Evidence from China

Abstract: We systematically examine the acute impact of exposure to a public health crisis on multiple dimensions of economic decision making and social preferences using unique experimental panel data collected just before and immediately after the outbreak of COVID-19 in China. Exploiting the geographical variation in virus prevalence and unique dataset of longitudinal experiments, we show that while social and economic preferences are largely stable, participants who were more intensely exposed to the virus became more anti-social than those with lower exposure. The effect is particularly pronounced for individuals who experienced an increase in depression or negative affect, which highlights the important role of psychological health as a potential pathway through which the virus outbreak affects behaviour. Our results have important policy implications, as pro-sociality is likely to affect how individuals adopt measures to protect themselves from COVID-19 and comply with public policy limiting its further spread.

Misunderstanding Nonlinear Prices: Evidence from a Natural Experiment on Residential Electricity Demand

Abstract: This paper examines how consumers respond to nonlinear prices. Exploiting a natural experiment with electricity consumers in British Columbia, I find evidence that some households severely misunderstand nonlinear prices—incorrectly perceiving that the marginal price applies to all consumption, not simply the last unit. While small in number, the exaggerated responses by these households have a large effect in aggregate, masking an otherwise predominant response to average price. Largely unexplored in the literature, this type of misunderstanding has important economic, policy, and methodological implications beyond electricity markets. I estimate the welfare loss for these households to be the equivalent of 10 percent of annual electricity expenditure.

Natural disaster and political trust: A natural experiment study of the impact of the Wenchuan earthquake:

Abstract: How do natural disasters impact political trust in contemporary China and what is the causal mechanism? Existing literature indicates that the severity of disaster, government relief effort and inf...

Does Broad-Based Merit Aid Improve College Completion? Evidence from New Mexico's Lottery Scholarship

Abstract: We use the natural experiment of a state lottery scholarship to measure the effect of generous financial aid on graduation rates at New Mexico's flagship public university. During the study period,...

How do People Respond to Small Probability Events with Large, Negative Consequences?

Abstract: We study how people react to small probability events with large negative consequences using the outbreak of the COVID-19 epidemic as a natural experiment. Our analysis is based on a unique administrative data set with anonymized monthly expenditures at the individual level. We find that older consumers reduced their spending by more than younger consumers in a way that mirrors the age dependency in COVID-19 case-fatality rates. This differential expenditure reduction is much more prominent for high-contact goods than for low-contact goods and more pronounced in periods with high COVID-19 cases. Our results are consistent with the hypothesis that people react to the risk of contracting COVID-19 in a way that is consistent with a canonical model of risk taking.

Is austerity responsible for the recent change in mortality trends across high-income nations? A protocol for an observational study.

Abstract: Introduction: Mortality rates in many high-income countries have changed from their long-term trends since around 2011. This paper sets out a protocol for testing the extent to which economic austerity can explain the variance in recent mortality trends across high-income countries. Methods and analysis: This is an ecological natural experiment study, which will use regression adjustment to account for differences in exposure, outcomes and confounding. All high-income countries with available data will be included in the sample. The timing of any changes in the trends for four measures of austerity (the Alesina-Ardagna Fiscal Index, real per capita government expenditure, public social spending and the cyclically adjusted primary balance) will be identified and the cumulative difference in exposure to these measures thereafter will be calculated. These will be regressed against the difference in the mean annual change in life expectancy, mortality rates and lifespan variation compared with the previous trends, with an initial lag of 2 years after the identified change point in the exposure measure. The role of underemployment and individual incomes as outcomes in their own right and as mediating any relationship between austerity and mortality will also be considered. Sensitivity analyses varying the lag period to 0 and 5 years, and adjusting for recession, will be undertaken. Ethics and dissemination: All of the data used for this study are publicly available, aggregated datasets with no individuals identifiable. There is, therefore, no requirement for ethical committee approval for the study. The study will be lodged within the National Health Service research governance system. All results of the study will be published following sharing with partner agencies. No new datasets will be created as part of this work for deposition or curation.

Promoting health equity through social capital in deprived communities: a natural policy experiment in Trieste, Italy.

Abstract: The Trieste Habitat Micro-area Programme (HMP), an innovative social-health service policy, has offered a natural experiment to empirically evaluate the social mechanisms through which social capital may have an impact on health inequalities. To date, literature clarifying this causal chain is scanty. This empirical study tested the following hypotheses: H1) innovative social-health practices can activate social mechanisms intentionally and systematically so as to generate social capital; H2) such social mechanisms increase specific properties of social capital, in particular those influencing more vulnerable individuals' relationships; H3) investing in these properties can enhance capabilities and, consequently, control over the health of more vulnerable individuals. The study was carried out during 2016-2018 and used both qualitative and quantitative methods. The qualitative part investigated the field experience of the HMP through interviews, focus groups and workshops with HMP professionals. The quantitative part assessed the effect HMP might have on these properties and the capacity to face health risks of more vulnerable individuals. Three samples, each of 200 individuals, residing in the target and in control areas were interviewed using a semi-structured questionnaire. One control sample was matched to the 200 treated subjects using a Propensity Score Matching. The results of the study suggest that the HMP intervention stimulated the development of empowerment, collaboration and interdependence among vulnerable people. This produced an increase in their social capital under several aspects, including enhanced trust, network extension and participation, cooperation and reciprocal help with neighbours, as well as improving their judgement on quality, timing and efficacy of the help received from institutions, relatives or friends. These findings show that socially shared relationships can create innovative local models of a universalistic generative welfare system, which would be both inclusive and able to enhance individual capabilities. These models could be disseminated and carried over to other contexts.

Pathogen Threat Increases Electoral Success for Conservative Parties: Results from a Natural Experiment with COVID-19 in France

Abstract: Conservative ideology is closely linked with pathogen prevalence, and adherence to conservative values increases under pathogen threat. To this day, few studies have demonstrated this effect using ecological data. For the first time, we analyse results from an election (the 2020 French local election) which was held during the growing COVID-19 spread in the country. Using mixed modelling on county-level data (N = 96), we show that perceived COVID-19 threat (search volume indices) but not real threat (prevalence rates) prior to the election are positively associated with an increase in conservative votes only. These results were robust to adjustment on several covariates including abstention rates, prior electoral scores for conservative parties and economic characteristics. Overall, a 1% increase in COVID-19 search volumes lead to an increase in conservative votes of .25%, 95%CI[.08,.41]. These results highlight the relevance of evolutionary theory for understanding real-life political behaviour and indicate that the current COVID-19 pandemic could have a substantial impact on electoral outcomes.

Natural Disasters and Informality: Are local labor markets impacted after an earthquake?

Abstract: This article studies the probability of being part of informal labor markets after a natural disaster. We consider different concepts of labor market informality and use empirical definitions for employment in the informal sector and informal employment. Since the Ecuadorian earthquake may be considered a natural experiment, we perform a two stage identification strategy using both coarsened exact matching (CEM), and nonlinear difference in differences (DD) using individual panel data. We use a fully exogenous measurement of intensity (Peak Ground Acceleration, PGA), which is continuous, and has not been subject to possible arbitrariness in its definition. We found that the earthquake had a positive effect in the likelihood of being part of informal sector if workers are located in the affected areas; we also identified significant gender differences, since a causal effect for men was found, but not for women. When we use the concept of informality based in jobs (informal employment) instead of companies (informal sector), no robust evidence of a causal effect was found. Our results suggest that the government's reconstruction efforts could had attenuated the effect of the disaster over informality in the most affected zones. © 2019 The Author(s). Regional Science Policy and Practice © 2019 RSAI

The Christmas Market Attack in Berlin and Attitudes Toward Refugees: A Natural Experiment with Data from the European Social Survey

Abstract: Using a quasi-experimental research design, this study examines changes in attitudes toward refugees after the terrorist attack on the Berlin Christmas market of December 19, 2016. In our analysis, we make use of random variation in the field period of the European Social Survey (ESS) to fashion a natural experimental design. The survey’s field period took place in Germany from August 23, 2016, to March 26, 2017. Hence, the Christmas market attack took place approximately halfway through the ESS’s field phase, thus making it possible to study the causal effect on changing attitudes toward minorities before and after the attack. We argue that the terrorist attack creates a spillover effect and negatively shapes public opinion of uninvolved ethnic minorities. Our data analysis suggests that immediately after the event, only people with a right-wing political attitude appear to be affected by the proposed spillover effect. However, we find that the worsening of attitudes toward refugees can also be observed in the general population as time progresses. We do not find variation according to educational levels.

Impacts from Delaying Access to Retirement Benefits on Welfare Receipt and Expenditure: Evidence from a Natural Experiment

Abstract: Governments are responding to fiscal pressures associated with ageing populations by increasing the eligibility age for publicly funded retirement benefits. However, recent studies show large resulting increases in the receipt of disability and unemployment benefits, which raises concern that welfare savings are offset by increased inflows into alternative payments. Using administrative data to examine the impacts of female eligibility age increases in Australia, we find little evidence of this. Instead, most of the increase is because the delay mechanically extends the receipt time of people already on alternative payments. The implication is that fiscal savings are not jeopardised by welfare substitution.

A natural experiment on job insecurity and fertility in France

Abstract: Job insecurity can have wide-ranging consequences outside of the labour market. We here argue that it reduces fertility amongst the employed. The 1999 rise in the French Delalande tax, paid by large private firms when they laid off workers aged over 50, produced an exogenous rise in job insecurity for younger workers in these firms. A difference-in-differences analysis of French ECHP data reveals that this greater job insecurity for these under-50s significantly reduced their probability of having a new child by 3.9 percentage points. Reduced fertility is only found at the intensive margin: job insecurity reduces family size but not the probability of parenthood itself. Our results also suggest negative selection into parenthood, as this fertility effect does not appear for low-income and less-educated workers.