Explaining feast or famine in randomized field trials. Medical science and criminology compared

Dietary interventions, the gut microbiome, and aggressive behavior: Review of research evidence and potential next steps

Research in biosocial criminology and other related disciplines has established links between nutrition and aggressive behavior. In addition to observational studies, randomized trials of nutritional supplements like vitamins, omega-3 fatty acids, and folic acid provide evidence of the dietary impact on aggression. However, the exact mechanism of the diet-aggression link is not well understood. The current article proposes that the gut microbiome plays an important role in the process, with the microbiota-gut-brain axis serving as such a mediating mechanism between diet and behavior. Based on animal and human studies, this review synthesizes a wide array of research across several academic fields: from the effects of dietary interventions on aggression, to the results of microbiota transplantation on socioemotional and behavioral outcomes, to the connections between early adversity, stress, microbiome, and aggression. Possibilities for integrating the microbiotic perspective with the more traditional, sociologically oriented theories in criminology are discussed, using social disorganization and self-control theories as examples. To extend the existing lines of research further, the article considers harnessing the experimental potential of noninvasive and low-cost dietary interventions to help establish the causal impact of the gut microbiome on aggressive behavior, while adhering to the high ethical standards and modern research requirements. Implications of this research for criminal justice policy and practice are essential: not only can it help determine whether the improved gut microbiome functioning moderates aggressive and violent behavior but also provide ways to prevent and reduce such behavior, alone or in combination with other crime prevention programs.

Research that Guides Practice: Outcome Research in Swedish PhD Theses Across Seven Disciplines 1997-2012

The core of evidence-based practice (EBP) as advocated for within the practice arms of the health and social sciences is to promote the routine incorporation of the best available research evidence into practice efforts. This requires discipline-specific education that is not only grounded in professional practice but also prepares would-be scientists in the application of the sophisticated techniques that characterize today's high research standards. Doctoral-level education is an important primer for future scientific endeavors across disciplines. This study examined 2334 theses published across Sweden in public health, criminology, nursing, psychiatry, psychology, social work, and sociology during the period 1997-2012. Of the theses reviewed, 13% aimed to investigate the effects of interventions. The highest percentage of effectiveness studies was found in nursing, public health, and psychology. The percentage of outcome research increased during the period. Controlled studies (with comparison group and pre- and post-test) occurred primarily within public health, nursing, psychiatry, and psychology. Of the 296 theses that included an intervention effectiveness study, 131 (44%), or 5.6% of all theses reviewed, met all four assessment criteria for quality. PhD education across seven disciplines in Sweden may be producing a professional core of scientists that is ill prepared to produce the type of research that is necessary to inform practice of the effects of its interventions as exposure to the rigors of quality effectiveness research is all but non-existent. This has implications for the advancement of an evidence-based practice and intervention science more broadly.

The Need for Experimental Methodology in Intimate Partner Violence: Finding Programs That Effectively Prevent IPV

The lack of rigorous evaluations of intimate partner violence (IPV) programs has severely limited our knowledge about what works. However, IPV programs can be rigorously evaluated through randomized controlled trials (RCTs) conducted ethically and safely. This article provides an example of how a RCT to test an IPV preventive intervention—the Enhanced Nurse Family Partnership Study ( ENFPS)—was successfully implemented by a partnership of researchers and practitioners. The article concludes with some recommendations, arrived at by the researchers and practitioners on the ENFPS team, for achieving a successful collaboration thought to be essential in executing a field experiment.

A statistical perspective on the design of drug-court studies

Recent meta-analyses of drug-court studies recognized the poor methodological quality of the evaluations, with only a few being randomized. This article critiques the design of the randomized studies from a statistical perspective. Learning points are identified for future drug-court studies and are applicable to evaluations both of other specialist courts and of court-based interventions more generally. The specific issues covered are randomization, describing the intervention, and baseline characteristics; study outcomes, and sample size calculations; in-program and postprogram behavior, analysis plan, and presentation of results.

A short history of randomized experiments in criminology. A meager feast

This article discusses advantages of randomized experiments and key issues raised in the following articles. The main concern is the growth and decrease in the use of randomized experiments by the California Youth Authority, the U.S. National Institute of Justice, and the British Home Office, although other experiments are also discussed. It is concluded that feast and famine periods are influenced by key individuals. It is recommended that policy makers, practitioners, funders, the mass media, and the general public need better education in research quality so that they can tell the difference between good and poor evaluation studies. They might then demand better evaluations using randomized experiments.

Ethical practice and evaluation of interventions in crime and justice. The moral imperative for randomized trials

In considering the ethical dilemmas associated with randomized experiments, scholars ordinarily focus on the ways in which randomization of treatments or interventions violates accepted norms of conduct of social science research more generally or evaluation of crime and justice questions more specifically. The weight of ethical judgment is thus put on experimental research to justify meeting ethical standards. In this article, it is argued that just the opposite should be true, and that in fact there is a moral imperative for the conduct of randomized experiments in crime and justice. That imperative develops from our professional obligation to provide valid answers to questions about the effectiveness of treatments, practices, and programs. It is supported by a statistical argument that makes randomized experiments the preferred method for ruling out alternative causes of the outcomes observed. Common objections to experimentation are reviewed and found overall to relate more to the failure to institutionalize experimentation than to any inherent limitations in the experimental method and its application in crime and justice settings. It is argued that the failure of crime and justice practitioners, funders, and evaluators to develop a comprehensive infrastructure for experimental evaluation represents a serious violation of professional standards.