The Institute of Medicine (IOM) defines a conflict of interest as “a set of circumstances that creates a risk that professional judgment or actions regarding a primary interest will be unduly influenced by a secondary interest” [15]. Conflicts of interest are a problem for those who must make expert judgments on behalf of others; thus, their primary interest is the well-being of those who rely upon these judgments. For researchers, this is the scientific community and public, who make decisions on the basis of the outcomes of research. Conflicts of interest are distinct from ethical dilemmas in that one interest has a claim to priority—the primary or professional interest—and efforts are directed at ensuring that secondary interests do not dominate, or appear to dominate, the primary interest [14].

Being a researcher means having particular education and training, typically a personal interest in a topic or field, usually employment with some kind of academic or scientific institution, and a whole host of experiences that make up a research career. These interests are part of the primary roles and responsibilities that come with being a scientist [13]. However, interests are distinct from conflicts of interest (Box 2).

We propose three rules of thumb to distinguish conflicts of interest from “interests” more broadly. First, it is theoretically possible, though not always necessary, to eliminate a conflict of interest. For example, an investigator can divest themselves from shares in the company that commercializes their research product, whereas they cannot possibly separate themselves from their disciplinary training. Similarly, if the only solution for a particular type of interest is recusal because the interest cannot be eliminated, this is not a conflict of interest but rather part of the researcher’s professional role or personal identity.

Second, the direction of the bias produced by a conflict of interest is consistent within a set of circumstances. Evidence examining the influence of industry sponsorship on research suggests that the existence of these conflicts may systematically distort the outcomes, effect sizes, or conclusions of research in a direction which consistently favors the sponsor [7–11].

Third, conflicts of interest can be widespread, and their scope of influence may extend far beyond an individual. People participate in research as individuals, and each bring their experiences and personal and professional interests to the process. However, sponsorship serves to amplify a particular viewpoint, ensuring its widespread dissemination and representation in decision making. For example, corporate sponsorship of research is capable of distorting an entire body of published research, as was the case with the tobacco industry and research on secondhand smoke [16].

Conflicts of interest are not exclusively financial: for example, conflicts of interest can arise from personal relationships. First, a person theoretically can eliminate the conflict by eliminating the relationship (which in most cases is an extreme measure) or, more commonly, by reorganizing roles and responsibilities or seeking oversight. For example, spouses working in the same lab commonly require special permission from the institution and are not allowed to directly supervise each other. Recusal is a common strategy but, importantly, not the only option. For example, individuals disclose the relationship and typically recuse themselves from reviewing grant applications written by their students, postdocs, collaborators, rivals, or family members. Second, the direction of the bias can almost always be predicted with conflicts of interest arising from personal relationships—individuals will typically help their friends and harm their enemies. However, while personal relationships can lead to conflicts of interest, unlike conflicts of interest arising from financial ties, their effects rarely extend beyond the immediate situation. That said, conflicts of interest stemming from relationships may be more damaging for individuals in positions of power (such as supervisory or leadership roles), as their scope of influence is greater.

Commercial sponsorship of research and investigator financial conflicts of interest are two forms of conflict of interest with the strongest evidence base, suggesting that they are a widespread and harmful source of bias. Pharmaceutical, tobacco, food, or chemical industry funding biases human research studies towards outcomes that are favorable to the sponsor’s product, even when controlling for other biases in the methods [7–8,10–11,17]. Thus, even when the methods meet high standards for internal validity, financial conflicts of interest may influence research results through other mechanisms, such as the framing of the question, how the study is actually conducted, and whether it is fully and accurately reported.

While everyone comes to the table with an identity, past experiences, and professional interests, industry sponsorship or investigator payments serve as a megaphone, amplifying and multiplying a set of interests that align with the sponsor’s and thereby create a widespread platform of influence for the sponsor. The tobacco industry for decades used sponsorship of research and payments to scientists to fund research that supported their interests, to suppress research that did not, and to disseminate interest group data to the lay press and policymakers [16]. The influence of industry sponsorship on research has created a crisis within biomedicine—not only of confidence in the evidence that underlies clinical practice and public policy, but the integrity of the research itself. For example, Coca-Cola’s sponsorship of public health research resulted in the reshaping of an entire field of research to focus on physical activity to reduce obesity, to the exclusion of nutrition-related research [18].

The growing concern about “nonfinancial” interests may be part of the recognition that the social context in which research is conducted influences the results. For example, researchers conducted replications of 100 experimental and correlational studies in psychology and found that over half of the replications produced weaker evidence for the original findings, despite attempts to use the author’s original materials [19]. This suggests that something other than the research design produced such variation. In science, there has been a common pretext that the researcher should approach the research without any desire to influence the outcome and that any conclusions should be driven solely by the data. Social scientists, however, have long argued that it is not possible to be impartial, disinterested, or value-neutral and that it is essential to acknowledge this as a means of being answerable for what science claims to know about the world [20–21]. Feminist scholars in particular have argued that it is not possible to be neutral in research as it is neither possible nor even desirable for scientists to be interest-free [21–22]. While it is essential to systematically examine all of the social values shaping a research process, these cannot possibly be eliminated but must instead be made visible and open to critical interpretation [23]. However, this does not mean that one cannot be objective or that all interests and values are merely relative. Instead, scholars have advocated for a “passionate detachment,” which emphasizes fairness, honesty, and recognition of the social positions and interests that influence how evidence is produced and shared [20–21].

Recognizing that scientists possess an interested view—grounded in personal experiences and beliefs, education and disciplinary training, and intellectual commitments—is crucial to rigorous research and healthy scientific debate, but it is distinct from conflict of interest. Scientists cannot be separated from their interests or their social position in the world. Recusal of scientists based on their personal beliefs and experience can serve exclusionary purposes and falsely identify certain individuals, who also possess personal beliefs and experiences, as “objective,” narrowing the diversity of perspectives involved in decision making. For example, a recent analysis of recusals from Food and Drug Administration (FDA) advisory committees on the basis of “intellectual conflicts of interest” found that each instance led to a decision that favored industry interests and that no expert had been excluded because he or she supported a particular drug or device [24]. Similarly, the effect of interests on research is isolated to the sphere of influence of the individual, and the direction of the bias created cannot be predicted. A scientist seeking academic glory may do so on either side of a research agenda—for example, climate scientists and climate change-deniers have achieved equal renown. It could be argued that researchers’ personal and intellectual interests are fundamental to good research and that these interests provide the momentum for scientific ideas to persist long enough to be scrutinized and, ultimately, to be useful.

Confusing “interests” with “conflicts of interests” makes conflicts of interest appear so pervasive that they cannot be avoided but only disclosed. Rather, there are precedents for disclosing and managing financial conflicts of interest, which should be adopted and enforced widely within biomedical research institutions.

Disclosure is only a first step: requirements for disclosing financial conflicts of interest should be enforced, clear, and should list examples of financial conflicts of interest, following the example of the ICMJE [25]. Most disclosure policies currently rely on self-report; however, regulation such as the United States Physician Payments Sunshine Act could be expanded to include researchers and institutions to provide a more comprehensive source of data on financial conflicts of interest. While disclosure is essential in order to understand the scope of the problem and its effects, it is necessary that policy action go beyond disclosure to ensure that disclosures do not provide a moral license to dispense with their actual management [26].

Organizations, such as research institutions, scientific journals, and grant review panels should have policies for reviewing, mitigating, or eliminating financial conflicts of interest, and these should be enforced. Before engaging with a commercial entity, the proposed interaction should be subject to a thorough risk–benefit assessment by the research institution that includes the risk for reputational damage or loss of trust in the research activity [27]. For example, the Charles Perkins Centre at the University of Sydney has guidelines that require a committee to assess the alignment of a sponsor with the Centre’s mission; potential influence on the design, conduct, and publication of research; and the reputational risk to the institution [27]. Researchers should not engage with industry when the commercial interests are not aligned with improved public health or when the sponsor has any control over the design, conduct, or dissemination of the project [27]. Scientific institutions should consider prohibiting the acceptance of funding or publication of research when industry sponsorship or investigator conflicts of interest pose too high a risk. For example, several biomedical journals will not publish tobacco industry–funded research [28], and some universities do not accept tobacco industry funding for research [29].

The biomedical community needs new tools to account for the influence of interests and identities more generally on research. Reflexivity is a tool that could be borrowed from the social sciences and adapted to biomedical research that makes transparent and accounts for researchers’ professional and personal identities. It can be implemented at the level of the individual scientist but perhaps can be more effective when built into existing institutional processes. For example, if a university wished to set up a center on reproductive technology using CRISPR to genetically modify embryos, the steering committee would be well served to identify personal interests and past experience with the issue. Experts and those with particular opinions on the matter would not be recused, but perhaps opposing perspectives would be purposely included and processes put in place to ensure fair representation and an evidence-informed approach [30]. In lab settings, reflexivity has been used to make day-to-day research decisions transparent and to evaluate these decisions in terms of the interests at play [31–32]. Box 3 outlines key questions that are characteristic of reflexive processes [33].

We use a grant funding review panel as an example in Table 1 to show how two parallel processes can be used simultaneously: reflexive processes to address relevant interests and comprehensive disclosure and management for conflicts of interest (Table 1). These practices could also be useful at the research agenda–setting phase, in determining funding priorities, or in peer review processes. The goal is to hold researchers accountable without discrediting scientific findings and claims as mere “personal biases” [33] and to ensure fair representation rather than excluding certain individuals based on their personal characteristics, beliefs, or expertise.

The muddying of the waters around conflicts of interest serves to erode the political will to identify and manage conflicts of interest in scientific research, as they are portrayed as increasingly ubiquitous and unsolvable. A substantial evidence base supports the need for continued policy action, particularly around the disclosure and management of commercial sponsorship of research and investigator financial conflicts of interest. Different strategies are needed to manage interests more broadly to ensure fair representation and accountability.