This paper introduces the concept of the regulatory ethos to describe some common values and ideals that underscore the close connection between validation and regulation that this issue of BJHS Themes explores. We identify the primary motivation for this ethos as making knowledge production processes traceable, and define the regulatory ethos as valuing plans over situated actions, uniformity over heterogeneity, auditing over communication, and validation over validity. Standard operating procedures, reporting checklists, preregistrations, compliance rules and monitoring are key means through which this ethos is enacted. While regulators have been instrumental in promulgating this ethos, it is not confined to the regulatory sphere. We argue that reforms aimed at enhancing rigour and reproducibility are an example of how the practices and values associated with regulatory science have diffused out into academic science. Identifying this ethos as regulatory in origin – rather than wholly new or as part of a broader process of modernization – allows us to see that alternatives are not unscientific per se, and better identify the strengths and weaknesses of the regulatory ethos of science, such as the risk that data produced through these procedures will be replicable, statistically rigorous, and transparent, but not meaningful.

Since the mid-twentieth century, foreign-physician migration to the United States has challenged mainstream medicine. Facing simultaneous demands to address physician shortages and concerns about the quality of foreign-trained doctors, regulators struggled to create effective systems for evaluating international credentials. This essay traces three pivotal episodes reflecting the evolution of this regulatory landscape: the postwar incorporation of Jewish émigré doctors, the rise of Asian physician migration following the Hart-Celler Immigration and Nationality Act of 1965, and the contemporary role of global regulatory entities. Over the past sixty years, as physician migration from the global South has increased, the regulatory apparatuses to facilitate this mobility have grown in scale, size and number. The multiplication of these supranational bureaucracies and institutions is not a value-neutral endeavour. It reflects racialized assumptions coded through ‘competence’ discourses, geopolitical investments and a bias toward global North educational models, and raises broader questions about global health care equity. Despite these overlapping and sometimes redundant global-governance structures, however, foreign-physician integration continues to raise questions about trust, equivalency and the variability of human capital.

This paper uses the introduction at the US Food and Drug Administration of dose–response extrapolation for ascertaining toxicity between 1950 and 1980 to analyse the negotiations between statistical knowledge and regulation. Those statistical methods enabled experimental results to be translated into a ‘safe dose’ of a substance for human consumption, but different methods continued to give different estimates of effects, and there was little basis for determining which methods were most accurate. I argue that statisticians were not proposing their discipline so much as a tool for mechanical decision making than as a set of methods for establishing a regulatory procedure that made assumptions and judgements visible. Consequently, their use did not bring debates about low-dose toxicity to a close even as they promoted a regulatory ethos and enabled regulators to act, even in cases of inherent uncertainty and inescapable variability.

This essay examines how the interplay between diagnostic machines and patient experience reshaped the meaning of testing validity, through a 1926 malpractice lawsuit in colonial Shanghai. It traces how complaints of dizziness, a seemingly mundane side effect of new glasses, escalated into a legal and epistemic dispute over the validity of a vision test. Weaving together competing perspectives presented in court, the essay uncovers discrepancies between the examiner’s observations, the machine’s readings and the patient’s embodied experience. These clashes expose the fragility of the new regime of ‘scientific testing’ in the global city of Shanghai, which claimed authority from the emerging profession of optometry and a diagnostic machine known as the retinoscope. The case, I argue, marks an inflection point in the history of testing, as patient experience was recalibrated through new machines, re-legitimized in novel ways, and transformed into a generative feature of diagnostic practice itself.

Since the 1950s, US officials have sought to reduce cancer incidence by regulating chemical exposures. However, rodent carcinogenicity tests are lengthy and expensive, making it impractical to identify carcinogens among the tens of thousands of chemicals on the market through animal testing. Introduced in 1973, the quick and inexpensive ‘Ames test’ indicated whether a chemical caused mutations in bacteria, and putatively cancer in humans. In the 1970s and 1980s, scientific societies, international bodies and government agencies launched efforts to validate the Ames test for carcinogenicity. While the Ames test became the most commonly used mutagenicity (or genotoxicity) test, technical determinations of its validity could not resolve policy issues concerning how much predictiveness was required for regulatory action. The availability of new animal carcinogenicity data through the 1980s affected calculations of the predictiveness of the Ames test for carcinogenicity, and criticisms of the rodent bioassay also complicated the interpretation of mutagenicity data. This article documents the challenges of validating even a very successful chemical safety test, while paying attention to how academic scientists, government agencies and international bodies participated (and sometimes competed) in setting regulatory standards.

In post-war Britain there was cross-party political pressure to ensure that disabled veterans received fair compensation. This produced a particular challenge to the state’s deployment of psychiatric knowledge. In 1943 new laws governing the pension appeal tribunals were passed to give veterans the benefit of the doubt in their appeals, throwing the spotlight on diseases considered by psychiatrists to have hereditary aetiologies, such as schizophrenia. This paper reconstructs the medico-legal history of schizophrenia appeal cases to better understand both how the pursuit of judicial procedure interacted with medical uncertainty and how post-war sympathies for veterans helped to normalize schizophrenia in public life. Making invalidity fair meant ensuring that the government was held to the standards of legal procedure in its award of war disability pensions. Moreover, in the case of schizophrenia, it also meant using legal means to force the psychiatric profession to be more honest about the limits of its disease theories. The interaction of medical and legal epistemic practices produced a hybrid entity, stress-triggered schizophrenia, as a socially acceptable solution to the problem of medical uncertainty.

This paper examines how practices of validation linked epistemic authority to administrative power, transforming procedures of science into instruments of governance. In the 1880s, US government chemists founded the Association of Official Agricultural Chemists (AOAC) to resolve conflicting fertilizer analyses and secure public authority over commercial chemistry. Through multi-laboratory studies, the AOAC adopted methods that were judged to produce uniform results – a process later known as ‘validation’. In doing so, the AOAC transformed methodological agreement into a foundation for national regulation and helped define analytical chemistry as a trusted instrument of governance. Nearly a century later, in the 1970s, the AOAC attempted to apply similar principles to toxicity testing but failed: most toxicologists resisted standardization, and methodological uniformity did not yield uniform results. Where the AOAC faltered, the Organisation for Economic Co-operation and Development (OECD) succeeded, convening scientists and regulators across the industrialized world to establish standard methods for evaluating chemical risk. While the AOAC’s original validation system defended public authority against industrial interests, the OECD’s framework reinforced industry centrality by restricting regulatory legitimacy to ‘validated’ studies. Together these cases reveal how validation translated consensus into authority and aligned scientific reliability with political and economic order.

Animal models are essential in preclinical research and widely used in drug development, yet their legitimacy has long been debated. These debates intertwine epistemic, pragmatic, social, and ethical considerations. A key criterion for the legitimacy of an animal model is its validity, which assesses how well it serves as a proxy for human disorders and contributes to treatment development. The forced swim test (FST) is a particularly contested case, as criticism regarding its validity has fuelled controversy over its legitimacy. This article examines how validity arguments and non-epistemic factors have been intertwined to shape the legitimacy of the FST as an animal model in depression research. Although public actors have emphasized non-epistemic concerns, including pragmatic, social, and ethical considerations, such as animal welfare, the article shows how they have also utilized the academic controversy about FST’s validity to argue against its legitimacy for measuring the efficacy of drugs for human depression.

From the 1960s onwards, a growing number of national and international organizations began working to define more precisely what constitutes a carcinogenic exposure. The central question for these new groups of experts soon became what kinds of data authorities should rely on to govern chemicals and their uses. Drawing on new archival material from the World Health Organization’s International Agency for Research on Cancer, this paper examines the dramatic rise and contested decline of the animal bioassay for carcinogenicity in this domain. The legitimation of this type of study was inseparable from the very emergence of the institutional machinery responsible for controlling carcinogens. During the 1970s and 1980s, establishing the animal bioassay as evidence of carcinogenicity became a way for scientific and regulatory institutions to stabilize relations among themselves. But what had been done could also be undone. The validity of animal studies was challenged on the ground of possible high-dose artefacts in rodents, as well as on that of the emergence of new cellular tests promising to be quicker, cheaper and more precise. These criticisms destabilized the institutional order linked to the animal bioassay standard, even as actors managed to contain the threat – allowing these studies to remain at the core of the field.