This paper studies whether environmental enforcement powers should be assigned to central or regional authorities. We develop a two-stage model in which authorities choose inspection intensities under imperfect monitoring, then firms determine emissions and compliance behaviour. We show that centralized enforcement is generally more stringent unless there is a high level of heterogeneity across regions or authorities. Although decentralized enforcement may yield higher welfare when regional heterogeneity in inspection effectiveness is sufficiently large, moving from centralization to decentralization is not a Pareto improvement. We further show that when regional governments place relatively low weight on environmental quality, central and local authorities disagree over the preferred enforcement structure, generating potential intergovernmental conflict within environmental federalism.

Social network experiments provide a powerful framework for identifying causal network effects but also allow a specific form of network endogeneity. Random assignment eliminates the correlation between individual differences and treatment assignment but not between individual differences and treatment response. Individual differences can shape how participants enact their assigned networks. We use data from three networks to demonstrate an underappreciated approach for estimating causal network effects in the presence of endogeneity. The pre-experiment network captures individual differences, the treatment network defines the assigned structure, and the behavioral network reflects the interactions that occur during the experiment. Because the treatment network is exogenously assigned, it can serve as an instrument for the behavioral network, isolating the causal component of behavioral network effects. Using data from a coordination experiment, we estimate the causal effect of brokerage in the behavioral network on an important team outcome: perceived leadership. We also examine the influence of pre-experiment networks, finding that individuals who enter with closed networks sometimes emerge as brokers. The result shows that behavioral networks form through interdependent choices and interactions among multiple individuals and that endogenous network structures can generate effects beyond the control or intentions of any single individual.

Global demand for shark products has contributed to increased levels of illegal shark fishing, posing a significant threat to marine ecosystem health and the sustainability of related livelihoods. Despite increased management and policy attention, including bans on shark finning and harvesting of certain species, compliance is not universal, and unsustainable practices persist. In this study, we focus on illegal shark fishing by Sri Lanka’s semi-industrial fleet, aiming to explore fishers’ awareness, perceptions of, and compliance with measures introduced to curb unsustainable shark fishing. During January–June 2023, 254 questionnaire-based interviews and six focus group discussions were conducted at three harbours associated with previous illegal shark landings to explore awareness of regulations and potential drivers of non-compliance. Our findings suggest that only 9% of respondents were aware of all banned shark species, 12% landed banned sharks that were caught incidentally and 47% reported that illegal shark landings occur. Thematic analysis identified key drivers of non-compliance, including the economic importance of sharks, reluctance to discard sharks, lack of awareness of regulations and perceived corruption amongst management authorities. These findings underscore the need to incorporate human dimensions into policymaking and fisheries management to address the global issue of illegal shark fishing effectively. Additionally, we identify that local support is critical for the success and sustainability of shark conservation and management efforts.

Studies of political persuasion often use an exogenous encouragement as an instrument for persuasive messaging. However, for some people, such encouragement is insufficient, while for others, it is unnecessary. These individuals are excluded from methods that only estimate a treatment effect among compliers. Using the marginal treatment effect framework, we extend research finding that exposure to West German television increases support for communism. We find that, because of self-selection, for those who watch West German TV regardless of signal quality, i.e. always-takers, cutting off West German television would have increased support for communism. Our extrapolation shows that media choices reinforce, rather than mollify, political preferences.

Protected areas are under immense pressure to safeguard much of the remaining global biodiversity and can be strained by unpredicted events such as the Covid-19 pandemic. Understanding the extent of the effects of the pandemic on protected area management and conservation outcomes is critical for recovery and future planning to buffer against these types of events. We used survey and focus group data to measure the perceived impact of the pandemic on protected areas in Mexico and outline the pathways that led to these conservation outcomes. Across 62 protected areas, we found substantial changes in management capacity, monitoring and tourism, and a slight increase in non-compliant activities. Our findings highlight the need to integrate short-term relief plans to support communities dependent on tourism, who were particularly vulnerable during the pandemic, and to increase access to technology and technical capacity to better sustain management activities during future crises.

Instrumental-variable (IV) estimation is an essential method for applied researchers across the social and behavioral sciences who analyze randomized control trials marred by noncompliance or leverage partially exogenous treatment variation in observational studies. The potential outcome framework is a popular model to motivate the assumptions underlying the identification of the local average treatment effect (LATE) and to stratify the sample into compliers, always-takers, and never-takers. However, applied research has thus far paid little attention to the characteristics of compliers and noncompliers. Yet, profiling compliers and noncompliers is necessary to understand what subpopulation the researcher is making inferences about and an important first step in evaluating the external validity (or lack thereof) of the LATE estimated for compliers. In this letter, we discuss the assumptions necessary for profiling, which are weaker than the assumptions necessary for identifying the LATE if the instrument is randomly assigned. We introduce a simple and general method to characterize compliers, always-takers, and never-takers in terms of their covariates and provide easy-to-use software in R and STATA that implements our estimator. We hope that our method and software facilitate the profiling of compliers and noncompliers as a standard practice accompanying any IV analysis.

In 2009, the International Criminal Court (ICC) stepped into uncharted waters as it issued its first arrest warrant for a sitting head of state, then President of Sudan Omar Al-Bashir. Following the UN Security Council's referral of the situation in the Darfur region of Sudan to the ICC, Al-Bashir was charged by the Court with war crimes and crimes against humanity, and in 2010, he was also charged with genocide. As a consequence, all of the states parties to the Rome Statute had a duty to arrest Al-Bashir. Several states have nonetheless failed to arrest him during country visits, allowing Al-Bashir to evade the ICC. This has given rise to a number of cases before the ICC Chambers, including this Appeals Chamber judgment regarding the Hashemite Kingdom of Jordan.

On July 6, 2017, Pre-Trial Chamber II of the International Criminal Court (the Court or ICC)—composed of Judges Tarfusser, Perrin de Brichambaut, and Chung—held that South Africa violated the Rome Statute of the ICC (Rome Statute) by failing to arrest and surrender to the Court President Omar Al-Bashir of Sudan when he visited the country in June 2015. However, the Court did not refer the matter to the ICC Assembly of States Parties (ASP) or the United Nations Security Council (UNSC) pursuant to Article 87(7) of the Rome Statute. The decision added South Africa to a list of ICC state parties that have failed in their Rome Statute obligations with respect to the incumbent head of state of Sudan. It also marked the first time that the ICC Office of the Prosecutor (OTP), all ICC states parties, and the United Nations (UN) were invited to present their views and argue fully what is perhaps the most legally contentious and politically sensitive issue that the ICC has faced in its history.

Objective – To provide a relatively non-technical review of recent statistical research on the analysis and interpretation of the results of randomised controlled trials in which there are possibly all three of the following types of protocol violation: non-adherence to allocated treatment, contamination (that is, patients receiving treatments other than the one to which they were allocated) and attrition (missing outcome data). Methods – The estimation methods involve the use of potential outcomes (counterfactuals) in the definition of a causal effect of treatment and in drawing valid inferences concerning its size. Results – The methods are explained through the use of simple arithmetical expressions involving the counts from three-way contingency tables (Outcome by Treatment Received by Random Allocation). Illustration is provided through the use of a hypothetical data set. Conclusions – Recent advances in statistical methodology enable one to estimate treatment effects from the results of randomised trials in which the treatment actually received is not necessarily the one to which the patient was allocated. These methods allow one to make adjustments to allow for both non-compliance and loss to follow-up. Even for such a 'broken' randomised trial, inference concerning causal effects is safer than that from data arising from an observational study that never involved random allocation in the first place.