Exploring the Nature of Ethnic Disparities in Sentencing through Causal Inference

对于一个自由社会来说，没有什么原则比法律上的平等更基本，也没有什么公共行为比量刑听证会更清楚地体现了这一原则。可以理解的是，对量刑方面的种族差异的研究吸引了大量的研究努力。经验研究表明，少数民族罪犯在犯下类似罪行后，往往会受到比白人罪犯更严厉的惩罚。这些差异有非常详细的记录；在不同司法管辖区、罪行类型和判决结果之间得到证实。然而，有一个关键问题仍然存在：这种差距能被视为歧视的证据吗？基于真实案例的研究不能根据罪犯的种族随机化，因此，我们如何知道这些差异不是由于未观察到的相关案例特征？例如，如果白人罪犯比黑人罪犯更频繁地认罪，我们预计黑人和白人罪犯犯下的类似罪行的刑罚严重程度会有所不同。对这个问题的分析反应一直是“控制”任何相关的病例特征。但是，如果这些差异是基于案例特征--例如罪犯的危险性--而这些特征既不容易衡量，也不容易控制，那该怎么办？而且，如果这些案件特征不是中立地定义，而是受到潜在的歧视性做法的影响，该怎么办？这些都是尚未解决的重要方法问题。在这里，我们建议使用英国行政数据研究公司提供的新的量刑数据集，以及流行病学家开发的一些最新的敏感性分析技术来克服这一方法僵局。敏感性分析用于在可能违反关键研究假设的情况下测试结果的稳健性。最著名的例子可以追溯到“吸烟导致肺癌”的争论，由于缺乏实验证据，这场争论持续了几十年。这一直持续到康菲尔德等人。(1959)证明，任何相关的未观察到的因素(例如，在同时致癌的同时易患尼古丁渴求的基因)的影响应该是不切实际的高，以解释已观察到的肺癌和吸烟之间的联系。我们建议在这里遵循类似的方法。我们不是因为种族差异无法进行完美的“相似”比较而不加批判地对其不屑一顾，而是提出了以下问题：未被观察到的相关病例特征的力量应该是什么，才能解释观察到的种族差异？估计这一门槛将使我们能够对观察到的族裔差距是否代表歧视的证据作出更有见地的判断。除了学术价值外，本项目中要探讨的问题也是所有刑事司法机构的根本利益所在。该项目的各种要素，包括其研究问题，都是与英格兰和威尔士律师协会、量刑委员会、皇家检察院和量刑学院的代表合作共同设计的，这些机构是该项目的外部合作伙伴之一。因此，我们的调查结果将直接相关，并可供负责监测和纠正我们司法管辖区族裔差距的主要政策制定者使用。最终，该项目将有助于加强公众对全国刑事司法系统中种族差异的辩论。无论结果如何，对量刑方面的族裔差异进行独立和空前有力的审查将增加刑事司法系统的透明度，表明廉正，并有助于恢复公众的信任。

Few principles are more fundamental to a liberal society than equality under the law, and few public acts epitomise that principle more clearly than sentencing hearings. Understandably, the study of ethnic disparities in sentencing has attracted vast research efforts. Empirical studies have shown how offenders from ethnic minority groups tend to receive harsher punishments than white offenders after committing similar crimes. These disparities have been documented in great detail; being corroborated across jurisdictions, offence types, and sentence outcomes. However, one key question remains: can such disparities be taken as evidence of discrimination? Research based on real cases cannot randomise offenders by their ethnicity, hence, how do we know that those disparities are not due to unobserved relevant case characteristics? For example, we would expect to see differences in sentence severity for similar crimes committed by black and white offenders if white offenders are shown to plead guilty more often than black offenders. The analytical response to this problem has been to 'control for' any relevant case characteristics. But what if those differences are based on case characteristics - such as offender dangerousness - that cannot be easily measured, nor controlled for? And, what if those case characteristics are not neutrally defined but subject to potential discriminatory practices? These are important methodological questions that remain unresolved. Here, we suggest using the new sentencing datasets made available by Administrative Data Research UK, and some of the latest sensitivity analysis techniques developed by epidemiologists to overcome this methodological impasse. Sensitivity analysis is used to test the robustness of findings in contexts where key research assumptions are likely violated. The most famous example of this dates back to the 'smoking cause lung cancer' debate, which dragged on for decades because of the absence of experimental evidence. This was until Cornfield et al. (1959) demonstrated that the effect of any relevant unobserved factors (e.g. genes predisposing to nicotine craving while simultaneously carcinogenic) ought to be unrealistically high in order to explain the observed associations between lung cancer and smoking. We suggest following a similar approach here. Rather than uncritically dismissing ethnic disparities because of their inability to make perfect 'like with like' comparisons, we pose the following question: what should the strength of the unobserved relevant case characteristics be to explain away the ethnic disparities observed? Estimating that threshold will allow us to make a more informed judgement regarding whether the observed ethnic disparities represent evidence of discrimination. Beyond their academic merit, the questions to be explored in this project are of fundamental interest to all criminal justice agencies. Various elements of the project, including its research questions, have been co-designed in collaboration with representatives of the England and Wales Bar Association, Sentencing Council, Crown Prosecution Service, and Sentencing Academy, which feature amongst the project's external partners. As a result, our findings will be directly relevant and available to the key policy-makers in charge of monitoring and redressing ethnic disparities in our jurisdiction. Ultimately, this project will help enhance the public debate around ethnic disparities in the criminal justice system throughout the nation. Regardless of the findings obtained, undertaking an independent and unprecedentedly robust examination of ethnic disparities in sentencing will increase transparency in the criminal justice system, signalling integrity and contributing to restore public trust.