Detecting Spillover Effects: Design and Analysis of Multilevel Experiments

Interpersonal communication presents a methodological challenge and a research opportunity for researchers involved in field experiments. The challenge is that communication among subjects blurs the line between treatment and control conditions. When treatment effects are transmitted from subject to subject, the stable unit treatment value assumption (SUTVA) is violated, and comparison of treatment and control outcomes may provide a biased assessment of the treatment’s causal influence. Social scientists are increasingly interested in the substantive phenomena that lead to SUTVA violations, such as communication in advance of an election. Experimental designs that gauge SUTVA violations provide useful insights into the extent and influence of interpersonal communication. This article illustrates the value of one such design, a multilevel experiment in which treatments are randomly assigned to individuals and varying proportions of their neighbors. After describing the theoretical and statistical underpinnings of this design, we apply it to a large‐scale voter‐mobilization experiment conducted in Chicago during a special election in 2009 using social‐pressure mailings that highlight individual electoral participation. We find some evidence of within‐household spillovers but no evidence of spillovers across households. We conclude by discussing how multilevel designs might be employed in other substantive domains, such as the study of deterrence and policy diffusion.     

Computer‐Assisted Keyword and Document Set Discovery from Unstructured Text

The (unheralded) first step in many applications of automated text analysis involves selecting keywords to choose documents from a large text corpus for further study. Although all substantive results depend on this choice, researchers usually pick keywords in ad hoc ways that are far from optimal and usually biased. Most seem to think that keyword selection is easy, since they do Google searches every day, but we demonstrate that humans perform exceedingly poorly at this basic task. We offer a better approach, one that also can help with following conversations where participants rapidly innovate language to evade authorities, seek political advantage, or express creativity; generic web searching; eDiscovery; look‐alike modeling; industry and intelligence analysis; and sentiment and topic analysis. We develop a computer‐assisted (as opposed to fully automated or human‐only) statistical approach that suggests keywords from available text without needing structured data as inputs. This framing poses the statistical problem in a new way, which leads to a widely applicable algorithm. Our specific approach is based on training classifiers, extracting information from (rather than correcting) their mistakes, and summarizing results with easy‐to‐understand Boolean search strings. We illustrate how the technique works with analyses of English texts about the Boston Marathon bombings, Chinese social media posts designed to evade censorship, and others.     

Ethics in Criminal Justice: John Dewey Revisited

John Dewey has much to say to contemporary criminal justice educational strategies, particularly in respect to broadening the curriculum to include exposure to the humanities, values exploration, and moral decision-making. The case study method, coupled with Socratic teaching use of varied materials from the humanities, can approach an optimal learning experience within the Dewayan model. This educational model is offered in response to the calls for sensitive, holistic criminal justice practitioners in the modern age.     

Systemic Self-Regulation: A Framework for Trauma-Informed Services in Residential Juvenile Justice Programs

Most youth detained in juvenile justice facilities have extensive histories of exposure to psychological trauma. Traumatic stress plays a key role in their mental health and behavioral problems and needs, and in their safety and rehabilitation and the security and effectiveness of detention facilities. We provide an overview of the barriers to successful provision of mental health services for youths in juvenile justice facilities, including those involving youth, parents, and juvenile justice residential facility staff and administrators. Next, we discuss the relevance and potential utility of approaching mental health needs using posttraumatic stress disorder (PTSD), and more broadly posttraumatic dysregulation, as an organizing framework. Examples of how a posttraumatic dysregulation perspective can enhance juvenile justice residential facility milieus and services are presented, with an overview of traumatic stress intervention models that have shown promise, or potentially could be deployed, in developing and sustaining trauma-informed juvenile justice facilities.     

Forensic Identification of Seal Oils Using Lipid Profiles and Statistical Models

Seal blubber oils are used as a source of omega‐3 polyunsaturated fatty acids in Canada but prohibited in the United States and (FA) European Union. Thus, a reliable method is needed to identify oils originating from seals versus fish. Two lipid profiling methods, fatty acid analysis using gas chromatography and triacylglycerol (TAG) analysis using liquid chromatography and mass spectrometry, were applied with statistical models to discriminate commercial oils and blubber samples harvested from marine fish and seals. Significant differences were observed among FA profiles, and seal samples differed from each of the fish oils (p ≤ 0.001). FA and TAG profiles were used to discriminate sample groups using a random forest classifier; all samples were classified correctly as seals versus fish using both methods. We propose a two‐step method for the accurate identification of seal oils, with preliminary identification based on FA profile analysis and confirmation with TAG profiles.