Experimentally Testing the Effectiveness of Human Rights Treaties
International human rights law is a field concerned with causality. While scholars in other fields argue about how laws can be changed to maximize their effectiveness, scholars of international human rights law still regularly debate whether the major international agreements have had any effect on state behavior. Part of the reason that this threshold question is still contested is that there are a number of barriers to causal inference that make answering it with observational data incredibly difficult. Given these obstacles to using observational data, and the importance of the topic, scholars have begun to use experimental methods to study the effects of commitments to human rights agreements. This Essay discusses the motivations behind the limited experimental work on human rights, the mechanisms that are being tested, and the findings of this emerging literature.
International human rights law is a field concerned with causality. While scholars in other fields argue about how laws can be changed to maximize their effectiveness, scholars of international human rights law still regularly debate whether major international agreements have had any effect on state behavior. Some scholars have examined empirical records and concluded that under the right conditions, the ratification of human rights treaties is associated with improved human rights practices,1
For research that concludes that human rights treaties improve human rights practices, see Yonatan Lupu, Best Evidence: The Role of Information in Domestic Judicial Enforcement of International Human Rights Agreements, 67 Int’l Org. 469 (2013); Yonatan Lupu, Legislative Veto Players and the Effects of International Human Rights Agreements, 59 Am. J. Pol. Sci. 578 (2015); Daniel W. Hill, Estimating the Effects of Human Rights Treaties on State Behavior, 72 J. Pol. 1161 (2010); Beth A. Simmons, Mobilizing for Human Rights: International Law in Domestic Politics (2009).
For research that concludes that human rights treaties either have no (or at least a very small) effect on human rights practices, see, for example, Daniel W. Hill, Jr. & Zachary M. Jones, An Empirical Evaluation of Explanations for State Repression, 108 Am. Pol. Sci. Rev. 661 (2014); Eric A. Posner, The Twilight of International Human Rights Law (2014); Emilie M. Hafner-Burton & Kiyoteru Tsutsui, Human Rights in a Globalizing World: The Paradox of Empty Promises, 110 Am. J. Soc. 1373 (2005); Eric. Neumayer, Do International Human Rights Treaties Improve Respect for Human Rights?, 49 J. Conflict Resol. 925 (2005); Oona Hathaway, Do Human Rights Treaties Make a Difference?, 111 Yale L. J. 1935 (2002); Linda Camp Keith, The United Nations International Covenant on Civil and Political Rights: Does It Make A Difference in Human Rights Behavior?, 36 J. Peace Res. 95 (1999).
One thing that scholars agree on, however, is that if international human rights treaties were to change state behavior, it would not be because of the usual mechanism that drives compliance with international law: reciprocity.3
See Simmons, supra note 1, at 123 (“Human rights regimes do not involve reciprocal compliance. . . . No government is likely to alter its own rights practice to reciprocate for abuses elsewhere.”); Posner, supra note 2, at 79 (“In the case of ordinary treaties, the main reason that states comply with their obligations is that they fear that if they do not, other treaty parties will violate their own obligations. . . . [T]his logic does not easily carry over to human rights treaties.”).
This lack of consensus is in part due to the substantial obstacles that stand in the way of using observational data to study the causal effect of human rights treaties on state practices.4
The difficulties that arise when trying to empirically test compliance with human rights treaties have been well documented. For a general overview, see Adam S. Chilton & Dustin Tingley, Why the Study of International Law Needs Experiments, 52 Colum. J. Transnat’l L. 173 (2013). For a discussion focused on the problems posed by selection bias, see Yonatan Lupu, The Informative Power of Treaty Commitment: Using the Spatial Model to Address Selection Effects, 57 Am. J. Pol. Sci. 912 (2013). For a discussion of the bias in efforts to measure human rights violations, see Christopher J. Fariss, Respect for Human Rights Has Improved Over Time: Modeling the Changing Standard of Accountability, 108 Am. Pol. Sci. Rev. 297 (2014). For critical comments of approaches that have been used in the literature, see Eric A. Posner, Some Skeptical Comments on Beth Simmons’s “Mobilizing for Human Rights,” 44 NYU J. Int’l L. & Pol. 819 (2012).
See Fariss, supra note 4.
Given these obstacles to using observational data, and the importance of the topic, scholars have begun to use experimental methods to study the effects of commitments to human rights agreements. This is because experimental studies can be designed to test the plausibility of the mechanisms theorized as ways that the ratification of human rights treaties may change state behavior. Although experimental methods are unlikely to definitively establish whether international treaties improve human rights outcomes, the handful of experimental studies conducted to date have found that information on commitments to international agreements does have a modest impact on public opinion.6
Experiments studying international human rights law include: Adam S. Chilton, The Influence of International Human Rights Agreements on Public Opinion: An Experimental Study, 15 Chi. J. Int’l L. 110 (2014); Geoffrey P.R. Wallace, Martial Law? Military Experience, International Law, and Support for Torture, 58 Int’l Stud. Q. 501 (2014); Geoffrey P.R. Wallace, International Law and Public Attitudes Toward Torture: An Experimental Study, 67 Int’l Org. 105 (2013); Michael Tomz & Jessica L. P. Weeks, Human Rights, Democracy, and Public Support for War (Working Paper, Mar. 2015), (https://perma.cc/RLA5-78SU); Tonya L. Putnam & Jacob N. Shapiro, International Law and Voter Preferences: The Case of Foreign Human Rights Violations, Hum. Rts. Rev. Online (Apr. 7, 2017), (http://perma.cc/27L9-KTPD); Michael Tomz, Reputation and the Effect of International Law on Preferences and Beliefs (Working Paper, Feb. 2008), (https://perma.cc/Q6WF-48LW).
There are, however, several reasons why these experiments have extremely limited generalizability. This is not only because of the general problem that subjects often behave differently in experimental settings than they do in the real world, but also because the human rights experiments that have been conducted to date have largely relied on surveys administered to samples of Americans. As a result, although the evidence produced by these studies is informative, it does not offer any conclusive answers on whether human rights treaties change state behavior.
That said, these early studies have demonstrated that using experimental methods to study human rights may help bring new evidence to this important debate. Future work should build upon this foundation by expanding: the countries in which experiments are conducted; the topics that are studied; and the type of experiments being conducted. By building on existing studies in this way, experimental research on human rights may be able to provide crucial evidence that supplements what has been produced using observational research methods.
This Essay proceeds as follows. Section II discusses mechanisms that may lead states to improve their human rights practices as a result of signing human rights agreements. Section III summarizes the evidence from observational studies on whether those mechanisms have led states to improve their human rights practices. Section IV outlines why observational studies face difficulties trying to empirically test the effects of human rights treaties. Section V presents experimental studies that have tried to examine the effect of human rights agreements. Section VI discusses future directions that experimental research on human rights should take.
A central question in the study of international law is whether states change their behavior because of commitments to international agreements.7
For an example of the debate, compare Abram Chayes & Antonia Handler Chayes, On Compliance, 47 Int’l Org. 175 (1993) with George W. Downs, David M. Rocke, & Peter N. Barsoom, Is the Good News about Compliance Good News about Cooperation?, 50 Int’l Org. 379 (1996).
For longer discussions of the role of reciprocity in compliance with international law, see Jack L. Goldsmith & Eric A. Posner. The Limits of International Law (2005); Eric A. Posner & Alan O. Sykes, Economic Foundations of International Law (2013). In an example of an empirical work that explores the effects of reciprocity, James D. Morrow, Order Within Anarchy: The Laws of War as an International Institution (2014) shows that reciprocity drives compliance with the laws of war.
See Posner, supra note 2, at 79.
See, for example, Dustin Tingley, Christopher Xu, Adam S. Chilton, & Helen Milner, The Political Economy of Inward FDI: Opposition to Chinese Mergers and Acquisitions, 8 Chinese J. Int’l Pol. 27 (2015) (finding that the U.S. is more likely to block attempts by Chinese companies to acquire American firms when China has previously blocked American companies in the same industries).
See Posner, supra note 2, at 79–82; Simmons, supra note 1, at 122.
Figure 1 illustrates some of the mechanisms through which commitments to international human rights treaties could result in changes to state behavior. The solid lines represent the commitments that states make to human rights treaties.12
The exact reason that states choose to commit to human rights treaties is a subject of debate. For example, it may be the case that states make commitments because of domestic considerations, or it may be the case that states sign agreements because they are persuaded to do so by other states with either carrots or sticks. For discussions of the topic, see Posner, supra note 2, at 59–68; Posner & Sykes, supra note 8, at 202–06; Simmons, supra note 1, at 57–111. For a recent empirical consideration of this topic, see Richard A. Nielsen & Beth A. Simmons, Rewards for Ratification: Payoffs for Participating in the International Human Rights Regime, 59 Int’l Stud. Q. 179 (2015).
Figure 1: Mechanisms Through Which Human Rights Treaties May Change State Behavior
[[{"fid":"511","view_mode":"full","fields":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""},"type":"media","field_deltas":{"1":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""}},"attributes":{"class":"media-element file-full","data-delta":"1"}}]]
The primary mechanism that has been theorized as driving compliance with human rights treaties—illustrated by the dashed loop below State A—is that ratification of human rights treaties may change the domestic political landscape of partially democratic countries in ways that make it easier for activists and opposition political parties to lobby for improved rights practices.13
For a discussion of the ways that ratifying human rights agreements may influence domestic politics and thus lead to changes in state behavior, see Simmons, supra note 1, at 125–48.
A second mechanism that may drive compliance with human rights treaties—illustrated by the dashed lines between countries—is “empathetic enforcement” by powerful states.14
I borrow the term “empathetic enforcement” from Beth Simmons. See Simmons, supra note 1, at 116. This mechanism is also often referred to simply as “coercion” by powerful states. For a discussion of the mechanism and examples of where it has been used, see Goldsmith & Posner, supra note 8, at 115–17.
A third mechanism that may drive compliance with human rights agreements—illustrated by the dashed line from the treaty to the states—is pressure applied by the international treaty bodies themselves.15
It is worth noting that scholars have largely been skeptical that this mechanism could actually lead states to change their behavior. See Posner, supra note 2, at 95–104; Emilie M. Hafner-Burton, Making Human Rights a Reality 44–66 (2013); Simmons, supra note 1, at 121–25.
A fourth mechanism that may lead states to improve human rights practices after ratifying international agreements—illustrated by the dashed line from the NGOs to State A—is the influence of non-governmental organizations.16
For a discussion of the role that NGOs can play in promoting human rights, see Hafner-Burton, supra note 15, at 151–63. For skepticism about this possibility, see Posner, supra note 2, at 82.
Despite years of scholarship researching the four mechanisms discussed in the previous Section, it is still disputed whether any of the four are viable channels through which treaty commitments may result in improved human rights practices. In this Section, I will briefly discuss some of the empirical research that has used observational data to test whether these four mechanisms have caused states to change their behavior.17
A complete survey of the empirical human rights literature is beyond the scope of this Essay. For a short introduction to the empirical literature on human rights, see Adam S. Chilton & Eric A. Posner, The Influence of History on States’ Compliance with Human Rights Obligations, 56 VA. J. Int’l L. 211 (2016). For more thorough reviews, see Emilie M. Hafner-Burton, A Social Science of Human Rights, 51 J. Peace Res. 273 (2014); Emilie M. Hafner-Burton, International Regimes for Human Rights, 15 Ann. Rev. Pol. Sci. 265 (2012); Gregory Shaffer & Tom Ginsburg, The Empirical Turn in International Legal Scholarship, 106 Am. J. Int’l L. 1, 19–25 (2012); Beth Simmons, Treaty Compliance and Violation, 13 Ann. Rev. Pol. Sci. 273 (2010).
First, empirical research has examined whether domestic political mechanisms may lead states to improve their human rights practices after ratifying international treaties. In the most prominent research testing this theory, Beth Simmons tested the effectiveness of thirteen human rights treaties.18
Simmons, supra note 1.
Lupu, Legislative Veto Players, supra note 1.
Lupu, Best Evidence, supra note 1. Lupu’s claim is that the presence of an independent judiciary increases respect for the ICCPR for civil rights, but not for physical integrity rights. The theory Lupu puts forward to explain this finding is that an independent judiciary can police rights violations for issue areas where the standards, proof, or evidence production costs are low. For another empirical paper that considers the effectiveness of domestic legal institutions on compliance with human rights agreements, see Emilia Justyna Powell & Jeffery K. Stanton, Domestic Judicial Institutions and Human Rights Treaty Violations, 53 Int’l Stud. Q. 149 (2009).
Posner, supra note 2, at 76–78.
Second, empirical research has tested whether empathetic enforcement might cause states to improve their human rights behavior. One body of research testing this theory has examined whether aid donors have punished states that violate human rights by withholding aid.22
Richard A Nielsen, Rewarding Human Rights? Selective Aid Sanctions Against Repressive States. 57 Int’l Stud. Q. 791, 791–92 (2013).
Id. at 791.
See Simmons, supra note 1, at 116 (“If we are looking for empathetic enforcement [of human rights treaties] from other countries, we will be looking in vain for a long time.”); Posner, supra note 2, at 80–81 (“Even powerful countries often cannot exert sufficient pressure on a human rights violator to cause it to improve its behavior, because the target of sanctions can often retaliate by improving its ties with the sanctioning countries’ rivals.”).
Third, there has been limited research trying to test whether pressure from human rights treaty bodies leads states to improve their human rights practices. Since human rights bodies do not have any strong enforcement powers and countries do not uniformly take their obligations to report to human rights bodies seriously,25
See Cosette Creamer & Beth A. Simmons, Ratification, Reporting and Rights: Quality of Participation in the Convention Against Torture, 37 Hum. Rts. Q. 579 (2015).
James H. Lebovic & Erik Voeten, The Cost of Shame: International Organizations and Foreign Aid in the Punishing of Human Rights Violations, 46 J. Peace Res. 79 (2009).
Simmons, supra note 17, at 291.
Fourth, a handful of empirical studies have tried to test whether pressure from NGOs has led to improved human rights practices. This research has focused on whether efforts to “name and shame” countries for violation of human rights has led to better practices. In what is perhaps the most widely cited study on the subject, Emilie Hafner-Burton found that efforts to spotlight human rights violations by NGOs are associated with increased repression.28
Emilie Hafner-Burton, Sticks and Stones: Naming and Shaming the Human Enforcement Problem, 62 Int’l Org. 689 (2008).
Anna Schrimpf, Does INGO Activism Improve Human Rights Practices? Evidence from a Multi-Issue Analysis (Working Paper 2014).
Judith G. Kelley & Beth A. Simmons, Politics by Number: Indicators as Social Pressure in International Relations, 59 Am. J. Pol. Sci. 55 (2015).
As the preceding discussion hopefully made clear, a consensus among empirical researchers has not emerged on the question of whether ratification of international human rights agreements improves state behavior. Although this is likely in part because empirical scholarship on international law is relatively new, it is also because there are a number of factors that make it incredibly difficult to study the causal effects of human rights treaties using observational data.31
The following discussion is based on Chilton & Tingely, supra note 4. The discussion in Chilton & Tingley uses human rights law and international humanitarian law to make a broader point about empirical research in international law and also develops the arguments discussed here more fully. Additionally, the data in this essay was originally presented in Chilton & Tingley, supra note 4.
First, observational research on human rights treaties has difficulty accounting for selection bias. Selection bias exists when the assignment of a treatment variable is systematically related to the dependent variable of interest. For example, if the subjects given Drug X in a clinical trial were picked to receive the drug because they were the healthiest subjects in the group, any positive effect of the drug may be attributable to the fact that the receipt of the Drug X (the treatment) was related to likely health outcomes (the dependent variable). The same problem exists in studying human rights treaties. Countries do not enter into treaties randomly. Instead, countries voluntarily choose to enter into human rights agreements based on their preferences and planned policies. To be clear, it might be the case that countries decide to enter into agreements when they do not plan on complying, or that they enter into the agreements when they do. Either is problematic for empirical research. Although empirical researchers have developed strategies to try and account for this selection bias,32
For an excellent discussion of the ways that researchers have tried to account for selection bias while studying international law, see Lupu, supra note 4.
Figure 2: Number of Countries Party to Major Human Rights Treaties
[[{"fid":"516","view_mode":"full","fields":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""},"type":"media","field_deltas":{"2":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""}},"attributes":{"class":"media-element file-full","data-delta":"2"}}]]
Second, even if it were possible to account for selection bias, a basic requirement of causal inference is variance. Simply put, there must be variance in the explanatory variable of interest to be able to assess the impact that it has on a given dependent variable. For example, if everyone that contracted a new disease was given Drug X, it would be impossible to know the effectiveness of Drug X (which is exactly why clinical trials randomly give some subjects placebos). This basic requirement of causal inference is a major hurdle for studying human rights treaties because there is very little variance in applicability of the major international human rights agreements (and no variance in the applicability of the parts of human rights law that are considered part of customary international law). As Figure 2 shows, nearly every country has signed onto the major human rights treaties. To further illustrate this point, the red line is the number of countries that are currently members of the U.N. Since there are very few countries that are not party to the major human rights agreements, and countries that are not party to the agreement are likely not representative of the countries where human rights agreements are likely to have an effect, it is thus very difficult to understand the effectiveness of these agreements on human rights practices.
Figure 3: Ratification History of Major Human Rights Agreements
[[{"fid":"521","view_mode":"full","fields":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""},"type":"media","field_deltas":{"3":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""}},"attributes":{"class":"media-element file-full","data-delta":"3"}}]]
Third, the current lack of variance in ratification of major human rights treaties would not be as much of a problem if historically there had been variance in which countries were party to the treaties. If that were the case, it would be possible to study the period between when the treaty had opened for ratification and when nearly all countries joined the agreements. For the first major human rights treaties, this was the case. As Figure 3 shows, countries continued to ratify the Convention on Elimination of Racial Discrimination (CERD), the International Covenant on Civil and Political Rights (ICCPR), and the International Covenant on Economic, Social, and Cultural Rights (ICESCR) for the entire latter half of the twentieth century.33
It is important to note that the number of countries in the world also dramatically increased during this period. As a result, Figure 3 may suggest there was more variance in early years than there actually was. For example, in the early 1980s, when roughly 120 countries were party to the CERD, approximately 150 countries were members of the U.N.
In another example, 159 countries have signed the Convention on the Rights of Persons with Disabilities (CRPD) since it opened for signature in 2007. Convention on the Rights of Persons with Disabilities, May 30, 2007, 2515 U.N.T.S., available at (https://perma.cc/Q5LE-7HA9).
Figure 4: Countries that Have Made Commitments to Eliminate Torture
[[{"fid":"526","view_mode":"full","fields":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""},"type":"media","field_deltas":{"4":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""}},"attributes":{"class":"media-element file-full","data-delta":"4"}}]]
Fourth, another difficulty with conducting empirical research on the effectiveness of human rights treaties is that countries frequently have overlapping legal obligations. The problem is that it is only possible to understand the effect of a given variable if it is possible to isolate it from other variables that may be driving the outcome of interest. For example, if everyone that contracted a new disease were given both Drug X and Drug Y, it would be impossible to isolate the effects of Drug X and the effects of Drug Y (not to mention the effect of their interaction). The same problem often exists with international legal commitments. Countries often have signed multiple agreements that regulate human rights practices, have joined multiple organizations that monitor human rights compliance, and also have domestic laws that prohibit the same conduct as the international agreement. To illustrate this point, Figure 4 shows the number of countries that have signed the Convention Against Torture (CAT) and the number of countries that have provisions in their constitutions that prohibit torture.35
For information on the data on constitutional torture prohibitions used in this figure, see Adam S. Chilton & Mila Versteeg, The Failure of Constitutional Torture Prohibitions, 44 J. L. Studies 417 (2015). For another discussion of this issue, see Adam S. Chilton & Mila Versteeg, International Law, Constitutional Law, and Public Support for Torture, 3 Res. & Pol. 1 (2016).
Fifth, beyond the previous four concerns related to the ratification of human rights treaties, it is also the case that there are frequently only flawed measures of human rights practices available to use as dependent variables. Human rights treaties seek to protect a large number of rights. In fact, as Figure 5 shows, the number of rights protected by individual treaties ranges from eleven to fifty-eight. Currently, however, there is only data available on a handful of rights for a large number of countries. The result is that it is difficult to know whether a given treaty has improved rights because there are not good measures for all of the rights that any given treaty tries to protect.
Figure 5: Number of Rights Protected in Major Human Rights Agreements
[[{"fid":"531","view_mode":"full","fields":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""},"type":"media","field_deltas":{"5":{"format":"full","field_file_image_alt_text[und][0][value]":false,"field_file_image_title_text[und][0][value]":false,"field_caption[und][0][value]":"","field_photo_credit[und][0][value]":""}},"attributes":{"class":"media-element file-full","data-delta":"5"}}]]
Moreover, even if there was unbiased data for one of these rights—say the right of freedom of speech—it might be the case that the treaty improves protection for that right while making things worse for another dozen rights. That said, it is likely the case that all of the current data sources are biased. Recent research has shown that the most widely used dataset for human rights—the CIRI dataset—is systematically biased because reporting standards have changed over time.36
See Fariss, supra note 4. The CIRI dataset uses State Department and Amnesty International Reports to code the human rights practices of countries on a 3-point scale. Fariss, however, uses a sophisticated empirical model to show that these widely-used scores are biased because the reporting standards have changed over time. Although Fariss also has created an unbiased single measure of “repression” that can be used as a dependent variable, it is only one variable that does not cover all of the rights that treaties try to protect.
This is not a criticism of scholars that have used the CIRI data in their research (which I readily admit to being one of); using the CIRI data is a completely reasonable decision, given that it is the data source with the broadest coverage available. After Fariss, supra note 4, however, scholars should be aware of the limitations with the CIRI data and any other dataset that uses reports on human rights to code countries.
One advantage of experimental research is that experiments can be designed to help test the mechanisms discussed in Section II that have been theorized as driving compliance with human rights agreements while accounting for the barriers to inference discussed in Section IV. Of course, my claim is not that experiments can address all of these problems at once.38
Of course, experimental research has problems of its own—the most notable of which being external validity. The limitations of experimental research are briefly discussed in Section VI, infra.
There have been at least two experiments conducted that tested whether prior commitments to international agreements increased support for policy reforms that would make a state comply with its human rights obligations. In the first experiment designed to test this mechanism, Wallace conducted a survey on American adults to determine whether information on prior commitments to international law decreased support for torture.39
Wallace, International Law and Public Attitudes Toward Torture, supra note 6. A companion paper also analyzes the results of this experiment, but focuses on whether there is a differential treatment effect for respondents with military experience. See Wallace, Martial Law, supra note 6.
This summary only discusses on the primary manipulation in Wallace’s paper, but the paper also includes two other treatments and a related second experiment. See Wallace, International Law and Public Attitudes Toward Torture, supra note 6.
The second study designed to test the Domestic Politics mechanism is Chilton.41
Chilton, supra note 6.
Several experiments have tested whether information on international law makes respondents more likely to support efforts to change the policies of states that violate human rights. For example, Putnam and Shapiro (2013) tested respondents’ willingness to support economic sanctions against a foreign country because of its human rights violations.42
Putnam & Shapiro, supra note 6.
In a related earlier study, Tomz, supra note 6, also tested whether respondents were willing to support sanctions in response to human rights violations in Myanmar. The difference, however, is that in the international law treatment, respondents were told that the sanctions would violate international law. Tomz found that information on international law decreased support for the use of sanctions by seventeen percent.
In another experiment that tests support for empathetic enforcement, Tomz and Weeks examined factors that influence support for military intervention.44
Tomz & Weeks, supra note 6.
At least one experiment has tested whether treaty body pressure increases support for reforms aimed at improving human rights. Anjum, Chilton, and Usman conducted an experiment in Pakistan that tested whether learning that policy reforms aimed at improving women’s rights were proposed by the U.N. increases support for the reforms.45
Gulnaz Anjum, Adam S. Chilton, & Zahid Usman, United Nations Endorsement & Support for Human Rights: An Experiment on Women’s Rights in Pakistan, (U. of Chi. Coase-Sandor Inst. for L. & Econ. Research Working Paper No. 563, Apr. 2016).
A recent experiment has also tested how international human rights law may help with NGO advocacy. Hafner-Burton, LeVeck, and Victor conducted an experiment with experienced NGO professionals that had experience working on environmental issues and human rights.46
Emilie M. Hafner-Burton, Brad L. LeVeck, & David G. Victor, How Activists Perceive the Utility of International Law, 78 J. Pol. 167 (2016).
For another experiment examining how International Law can be effectively used by advocates, see Kayla Jo McEntire, Michele Leiby, & Matthew Krain, Human Rights Organizations as Agents of Change: An Experimental Examination of Framing and Micromobilization, 109 Am. Pol. Sci. Rev. 407 (2015).
Although the experimental research on human rights has suggested that information on human rights agreements may be able to change public opinion, there are serious limitations to the studies that have been conducted to date. Most notably, the fact that nearly all of the experiments on human rights have been conducted using vignette studies with respondents in the U.S. seriously limits the generalizability of the findings.48
But see Anjum, Chilton, & Usman, supra note 45.
First, experiments should be conducted in transitioning democracies. There is little evidence to suggest that human rights treaties have improved the rights practices of stable democracies or stable autocracies. Instead, the best available evidence suggests that human rights agreements are most likely to change the behavior of developing democracies.49
Simmons, supra note 1, at 152–53.
See Chilton, supra note 6; Wallace, supra note 6; Putnam & Shapiro supra note 6; Tomz & Weeks, supra note 6.
See, for example, Sarah Sunn Bush & Amaney A. Jamal, Anti-Americanism, Authoritarian Politics, and Attitudes about Women’s Representation: Evidence from a Survey Experiment in Jordan, 59 Int’l Stud. Q. 34 (2015); Graeme Blair, Kosuke Imai & Jason Lyall, Explaining Support for Combatants during Wartime: A Survey Experiment in Afghanistan, 107 Am. Pol. Sci. Rev. 679 (2013); Graeme Blair et al., Poverty and Support for Militant Politics: Evidence from Pakistan, 107 Am. Pol. Sci. Rev. 679 (2013).
Second, experimental research should explore a wider range of topics. For better or worse,52
Posner, supra note 2, argues that including too many rights in international agreements may have adverse consequences on rights protections.
See Chilton & Tingley, supra note 4, at 214.
Third, scholars conducting experiments on human rights should start to utilize field experiments. Although the survey experiments that have been conducted provide new data on the influence of human rights agreements on public opinion, it is not clear whether those differences in opinion translate into meaningful changes in the respondents’ behavior, and in turn, into changes in public policies. Researchers in a number of fields related to international law—including international economic regulation, international relations, and development economics—have begun to conduct field experiments to determine whether experimental interventions result in changes to real world behavior.54
See, for example, Michael G. Findley, Daniel L. Nielsen, & J.C. Sharman, Using Field Experiments in International Relations: A Randomized Experiment of Anonymous Incorporation, 67 Int’l Org. 657 (2013); James D. Fearon, Macartan Humphreys, & Jeremy M. Weinstein, Can Development Aid Contribute to Social Cohesion after Civil War? Evidence from a Field Experiment in Post-Conflict Liberia, 99 Am. Econ. Rev. 287 (2009); James Habyarimana et al., Why Does Ethnic Diversity Undermine Public Goods Provision?, 101 Am. Pol. Sci. Rev. 709 (2007).
Of course, even if future experimental research on the effectiveness of human rights law moves in the direction that I have outlined, it does not mean that any one study will be able to definitely demonstrate whether human rights treaties have improved human rights around the world. Instead, experimental methods can produce evidence that complements empirical research using observational data. This would make it possible to triangulate on the answer to whether human rights treaties improve respect for rights.
- 1For research that concludes that human rights treaties improve human rights practices, see Yonatan Lupu, Best Evidence: The Role of Information in Domestic Judicial Enforcement of International Human Rights Agreements, 67 Int’l Org. 469 (2013); Yonatan Lupu, Legislative Veto Players and the Effects of International Human Rights Agreements, 59 Am. J. Pol. Sci. 578 (2015); Daniel W. Hill, Estimating the Effects of Human Rights Treaties on State Behavior, 72 J. Pol. 1161 (2010); Beth A. Simmons, Mobilizing for Human Rights: International Law in Domestic Politics (2009).
- 2For research that concludes that human rights treaties either have no (or at least a very small) effect on human rights practices, see, for example, Daniel W. Hill, Jr. & Zachary M. Jones, An Empirical Evaluation of Explanations for State Repression, 108 Am. Pol. Sci. Rev. 661 (2014); Eric A. Posner, The Twilight of International Human Rights Law (2014); Emilie M. Hafner-Burton & Kiyoteru Tsutsui, Human Rights in a Globalizing World: The Paradox of Empty Promises, 110 Am. J. Soc. 1373 (2005); Eric. Neumayer, Do International Human Rights Treaties Improve Respect for Human Rights?, 49 J. Conflict Resol. 925 (2005); Oona Hathaway, Do Human Rights Treaties Make a Difference?, 111 Yale L. J. 1935 (2002); Linda Camp Keith, The United Nations International Covenant on Civil and Political Rights: Does It Make A Difference in Human Rights Behavior?, 36 J. Peace Res. 95 (1999).
- 3See Simmons, supra note 1, at 123 (“Human rights regimes do not involve reciprocal compliance. . . . No government is likely to alter its own rights practice to reciprocate for abuses elsewhere.”); Posner, supra note 2, at 79 (“In the case of ordinary treaties, the main reason that states comply with their obligations is that they fear that if they do not, other treaty parties will violate their own obligations. . . . [T]his logic does not easily carry over to human rights treaties.”).
- 4The difficulties that arise when trying to empirically test compliance with human rights treaties have been well documented. For a general overview, see Adam S. Chilton & Dustin Tingley, Why the Study of International Law Needs Experiments, 52 Colum. J. Transnat’l L. 173 (2013). For a discussion focused on the problems posed by selection bias, see Yonatan Lupu, The Informative Power of Treaty Commitment: Using the Spatial Model to Address Selection Effects, 57 Am. J. Pol. Sci. 912 (2013). For a discussion of the bias in efforts to measure human rights violations, see Christopher J. Fariss, Respect for Human Rights Has Improved Over Time: Modeling the Changing Standard of Accountability, 108 Am. Pol. Sci. Rev. 297 (2014). For critical comments of approaches that have been used in the literature, see Eric A. Posner, Some Skeptical Comments on Beth Simmons’s “Mobilizing for Human Rights,” 44 NYU J. Int’l L. & Pol. 819 (2012).
- 5See Fariss, supra note 4.
- 6Experiments studying international human rights law include: Adam S. Chilton, The Influence of International Human Rights Agreements on Public Opinion: An Experimental Study, 15 Chi. J. Int’l L. 110 (2014); Geoffrey P.R. Wallace, Martial Law? Military Experience, International Law, and Support for Torture, 58 Int’l Stud. Q. 501 (2014); Geoffrey P.R. Wallace, International Law and Public Attitudes Toward Torture: An Experimental Study, 67 Int’l Org. 105 (2013); Michael Tomz & Jessica L. P. Weeks, Human Rights, Democracy, and Public Support for War (Working Paper, Mar. 2015), (https://perma.cc/RLA5-78SU); Tonya L. Putnam & Jacob N. Shapiro, International Law and Voter Preferences: The Case of Foreign Human Rights Violations, Hum. Rts. Rev. Online (Apr. 7, 2017), (http://perma.cc/27L9-KTPD); Michael Tomz, Reputation and the Effect of International Law on Preferences and Beliefs (Working Paper, Feb. 2008), (https://perma.cc/Q6WF-48LW).
- 7For an example of the debate, compare Abram Chayes & Antonia Handler Chayes, On Compliance, 47 Int’l Org. 175 (1993) with George W. Downs, David M. Rocke, & Peter N. Barsoom, Is the Good News about Compliance Good News about Cooperation?, 50 Int’l Org. 379 (1996).
- 8For longer discussions of the role of reciprocity in compliance with international law, see Jack L. Goldsmith & Eric A. Posner. The Limits of International Law (2005); Eric A. Posner & Alan O. Sykes, Economic Foundations of International Law (2013). In an example of an empirical work that explores the effects of reciprocity, James D. Morrow, Order Within Anarchy: The Laws of War as an International Institution (2014) shows that reciprocity drives compliance with the laws of war.
- 9See Posner, supra note 2, at 79.
- 10See, for example, Dustin Tingley, Christopher Xu, Adam S. Chilton, & Helen Milner, The Political Economy of Inward FDI: Opposition to Chinese Mergers and Acquisitions, 8 Chinese J. Int’l Pol. 27 (2015) (finding that the U.S. is more likely to block attempts by Chinese companies to acquire American firms when China has previously blocked American companies in the same industries).
- 11See Posner, supra note 2, at 79–82; Simmons, supra note 1, at 122.
- 12The exact reason that states choose to commit to human rights treaties is a subject of debate. For example, it may be the case that states make commitments because of domestic considerations, or it may be the case that states sign agreements because they are persuaded to do so by other states with either carrots or sticks. For discussions of the topic, see Posner, supra note 2, at 59–68; Posner & Sykes, supra note 8, at 202–06; Simmons, supra note 1, at 57–111. For a recent empirical consideration of this topic, see Richard A. Nielsen & Beth A. Simmons, Rewards for Ratification: Payoffs for Participating in the International Human Rights Regime, 59 Int’l Stud. Q. 179 (2015).
- 13For a discussion of the ways that ratifying human rights agreements may influence domestic politics and thus lead to changes in state behavior, see Simmons, supra note 1, at 125–48.
- 14I borrow the term “empathetic enforcement” from Beth Simmons. See Simmons, supra note 1, at 116. This mechanism is also often referred to simply as “coercion” by powerful states. For a discussion of the mechanism and examples of where it has been used, see Goldsmith & Posner, supra note 8, at 115–17.
- 15It is worth noting that scholars have largely been skeptical that this mechanism could actually lead states to change their behavior. See Posner, supra note 2, at 95–104; Emilie M. Hafner-Burton, Making Human Rights a Reality 44–66 (2013); Simmons, supra note 1, at 121–25.
- 16For a discussion of the role that NGOs can play in promoting human rights, see Hafner-Burton, supra note 15, at 151–63. For skepticism about this possibility, see Posner, supra note 2, at 82.
- 17A complete survey of the empirical human rights literature is beyond the scope of this Essay. For a short introduction to the empirical literature on human rights, see Adam S. Chilton & Eric A. Posner, The Influence of History on States’ Compliance with Human Rights Obligations, 56 VA. J. Int’l L. 211 (2016). For more thorough reviews, see Emilie M. Hafner-Burton, A Social Science of Human Rights, 51 J. Peace Res. 273 (2014); Emilie M. Hafner-Burton, International Regimes for Human Rights, 15 Ann. Rev. Pol. Sci. 265 (2012); Gregory Shaffer & Tom Ginsburg, The Empirical Turn in International Legal Scholarship, 106 Am. J. Int’l L. 1, 19–25 (2012); Beth Simmons, Treaty Compliance and Violation, 13 Ann. Rev. Pol. Sci. 273 (2010).
- 18Simmons, supra note 1.
- 19Lupu, Legislative Veto Players, supra note 1.
- 20Lupu, Best Evidence, supra note 1. Lupu’s claim is that the presence of an independent judiciary increases respect for the ICCPR for civil rights, but not for physical integrity rights. The theory Lupu puts forward to explain this finding is that an independent judiciary can police rights violations for issue areas where the standards, proof, or evidence production costs are low. For another empirical paper that considers the effectiveness of domestic legal institutions on compliance with human rights agreements, see Emilia Justyna Powell & Jeffery K. Stanton, Domestic Judicial Institutions and Human Rights Treaty Violations, 53 Int’l Stud. Q. 149 (2009).
- 21Posner, supra note 2, at 76–78.
- 22Richard A Nielsen, Rewarding Human Rights? Selective Aid Sanctions Against Repressive States. 57 Int’l Stud. Q. 791, 791–92 (2013).
- 23Id. at 791.
- 24See Simmons, supra note 1, at 116 (“If we are looking for empathetic enforcement [of human rights treaties] from other countries, we will be looking in vain for a long time.”); Posner, supra note 2, at 80–81 (“Even powerful countries often cannot exert sufficient pressure on a human rights violator to cause it to improve its behavior, because the target of sanctions can often retaliate by improving its ties with the sanctioning countries’ rivals.”).
- 25See Cosette Creamer & Beth A. Simmons, Ratification, Reporting and Rights: Quality of Participation in the Convention Against Torture, 37 Hum. Rts. Q. 579 (2015).
- 26James H. Lebovic & Erik Voeten, The Cost of Shame: International Organizations and Foreign Aid in the Punishing of Human Rights Violations, 46 J. Peace Res. 79 (2009).
- 27Simmons, supra note 17, at 291.
- 28Emilie Hafner-Burton, Sticks and Stones: Naming and Shaming the Human Enforcement Problem, 62 Int’l Org. 689 (2008).
- 29Anna Schrimpf, Does INGO Activism Improve Human Rights Practices? Evidence from a Multi-Issue Analysis (Working Paper 2014).
- 30Judith G. Kelley & Beth A. Simmons, Politics by Number: Indicators as Social Pressure in International Relations, 59 Am. J. Pol. Sci. 55 (2015).
- 31The following discussion is based on Chilton & Tingely, supra note 4. The discussion in Chilton & Tingley uses human rights law and international humanitarian law to make a broader point about empirical research in international law and also develops the arguments discussed here more fully. Additionally, the data in this essay was originally presented in Chilton & Tingley, supra note 4.
- 32For an excellent discussion of the ways that researchers have tried to account for selection bias while studying international law, see Lupu, supra note 4.
- 33It is important to note that the number of countries in the world also dramatically increased during this period. As a result, Figure 3 may suggest there was more variance in early years than there actually was. For example, in the early 1980s, when roughly 120 countries were party to the CERD, approximately 150 countries were members of the U.N.
- 34In another example, 159 countries have signed the Convention on the Rights of Persons with Disabilities (CRPD) since it opened for signature in 2007. Convention on the Rights of Persons with Disabilities, May 30, 2007, 2515 U.N.T.S., available at (https://perma.cc/Q5LE-7HA9).
- 35For information on the data on constitutional torture prohibitions used in this figure, see Adam S. Chilton & Mila Versteeg, The Failure of Constitutional Torture Prohibitions, 44 J. L. Studies 417 (2015). For another discussion of this issue, see Adam S. Chilton & Mila Versteeg, International Law, Constitutional Law, and Public Support for Torture, 3 Res. & Pol. 1 (2016).
- 36See Fariss, supra note 4. The CIRI dataset uses State Department and Amnesty International Reports to code the human rights practices of countries on a 3-point scale. Fariss, however, uses a sophisticated empirical model to show that these widely-used scores are biased because the reporting standards have changed over time. Although Fariss also has created an unbiased single measure of “repression” that can be used as a dependent variable, it is only one variable that does not cover all of the rights that treaties try to protect.
- 37This is not a criticism of scholars that have used the CIRI data in their research (which I readily admit to being one of); using the CIRI data is a completely reasonable decision, given that it is the data source with the broadest coverage available. After Fariss, supra note 4, however, scholars should be aware of the limitations with the CIRI data and any other dataset that uses reports on human rights to code countries.
- 38Of course, experimental research has problems of its own—the most notable of which being external validity. The limitations of experimental research are briefly discussed in Section VI, infra.
- 39Wallace, International Law and Public Attitudes Toward Torture, supra note 6. A companion paper also analyzes the results of this experiment, but focuses on whether there is a differential treatment effect for respondents with military experience. See Wallace, Martial Law, supra note 6.
- 40This summary only discusses on the primary manipulation in Wallace’s paper, but the paper also includes two other treatments and a related second experiment. See Wallace, International Law and Public Attitudes Toward Torture, supra note 6.
- 41Chilton, supra note 6.
- 42Putnam & Shapiro, supra note 6.
- 43In a related earlier study, Tomz, supra note 6, also tested whether respondents were willing to support sanctions in response to human rights violations in Myanmar. The difference, however, is that in the international law treatment, respondents were told that the sanctions would violate international law. Tomz found that information on international law decreased support for the use of sanctions by seventeen percent.
- 44Tomz & Weeks, supra note 6.
- 45Gulnaz Anjum, Adam S. Chilton, & Zahid Usman, United Nations Endorsement & Support for Human Rights: An Experiment on Women’s Rights in Pakistan, (U. of Chi. Coase-Sandor Inst. for L. & Econ. Research Working Paper No. 563, Apr. 2016).
- 46Emilie M. Hafner-Burton, Brad L. LeVeck, & David G. Victor, How Activists Perceive the Utility of International Law, 78 J. Pol. 167 (2016).
- 47For another experiment examining how International Law can be effectively used by advocates, see Kayla Jo McEntire, Michele Leiby, & Matthew Krain, Human Rights Organizations as Agents of Change: An Experimental Examination of Framing and Micromobilization, 109 Am. Pol. Sci. Rev. 407 (2015).
- 48But see Anjum, Chilton, & Usman, supra note 45.
- 49Simmons, supra note 1, at 152–53.
- 50See Chilton, supra note 6; Wallace, supra note 6; Putnam & Shapiro supra note 6; Tomz & Weeks, supra note 6.
- 51See, for example, Sarah Sunn Bush & Amaney A. Jamal, Anti-Americanism, Authoritarian Politics, and Attitudes about Women’s Representation: Evidence from a Survey Experiment in Jordan, 59 Int’l Stud. Q. 34 (2015); Graeme Blair, Kosuke Imai & Jason Lyall, Explaining Support for Combatants during Wartime: A Survey Experiment in Afghanistan, 107 Am. Pol. Sci. Rev. 679 (2013); Graeme Blair et al., Poverty and Support for Militant Politics: Evidence from Pakistan, 107 Am. Pol. Sci. Rev. 679 (2013).
- 52Posner, supra note 2, argues that including too many rights in international agreements may have adverse consequences on rights protections.
- 53See Chilton & Tingley, supra note 4, at 214.
- 54See, for example, Michael G. Findley, Daniel L. Nielsen, & J.C. Sharman, Using Field Experiments in International Relations: A Randomized Experiment of Anonymous Incorporation, 67 Int’l Org. 657 (2013); James D. Fearon, Macartan Humphreys, & Jeremy M. Weinstein, Can Development Aid Contribute to Social Cohesion after Civil War? Evidence from a Field Experiment in Post-Conflict Liberia, 99 Am. Econ. Rev. 287 (2009); James Habyarimana et al., Why Does Ethnic Diversity Undermine Public Goods Provision?, 101 Am. Pol. Sci. Rev. 709 (2007).