University of Pennsylvania

Biomedical Graduate Studies
Responsible Conduct of Research (RCR) and Scientific Rigor and Reproducibility (SRR)

Peer Review


Peer review in science is the process by which one’s work and/or other contributions are evaluated by fellow scientists, ideally those who have the competencies and experience to understand the work fully. Peer review is key to the review of grant applications, manuscripts, and advancement. As unique and important as peer review might be, however, it is not perfect. Limitations include failure of reviewers to agree, undue influence of individual reviewers in consensus decisions, different outcomes depending on different reviewers, forms of bias that relate to institution, geography, race, and gender, and conflicts of interest.  These limitations, coupled often with the high stakes in what’s decided, necessitate ethical guidance.



Ethical obligations attending peer review almost all relate to protection and fairness for those whose work or performance is being evaluated and those conducting the review. This makes sense, as the circumstances requiring peer review can have significant professional consequences. Obligations of greatest importance are confidentiality, impartiality, and professionalism.

Confidentiality speaks mostly to protection. A grant application, for example, is a vehicle for the ideas, perspectives, and direction unique to an investigator. Moreover, preliminary results are almost always in part unpublished, and an experimental design complete with controls, diverse reagents, and statistical perspectives represents painstaking thought and detail. Indeed, writing a grant application is a process of conceptual synthesis viewed by many as one of the highest of intellectual exercises. In this sense, the investigator is especially vulnerable. Leaks of information contained within the application could jeopardize his or her success for years to come. A related set of concerns exists for manuscripts submitted for publication. The intent of publication is, of course, to communicate one’s results to the scientific community, but publication and keeping one’s cards close to the vest exist in tension. Every author expects protection of his or her data throughout the review process so that a competitor does not gain an undue advantage. Protection in the case of a promotional process is different. The concern here is that information related to an individual’s progress and potential can, if leaked, unduly influence other professional endeavors, if not recruitment and advancement elsewhere. It is important to bear in mind, as well, that the concept of protection works in two directions. Confidentiality of the review process protects the reviewers from retaliation.

Impartiality relates more to fairness. It is often referenced in practical terms to the absence of a significant conflict of interest. Granting agencies and publishers have objective criteria for such conflicts. The NIH, for example, considers a significant conflict to exist in the review of a grant if the reviewer is from the same institution as the principal investigator or others on the application with a major role, if the reviewer has in the last three years been a collaborator or has had any other professional relationship with any person on the application who has a major role, or if the reviewer has a significant financial interest from the applicant institution, among other defined conflicts. But granting agencies and publishers are also quite concerned about the perception of conflict, which is less definitive. For the NIH, this is any situation that could cause a reasonable person with all the relevant facts to question the impartiality of the reviewer or that leads a reviewer to question his or her objectivity. This often arises when the reviewer is considered a competitor to the applicant.

Professionalism covers a wide range of behavior. As discussed in Responsible Conduct of Research, reviewers should be able to conduct careful, thorough, and critical reviews of papers or proposals through having appropriate expertise and providing sufficient time. They should avoid insults and unprofessional remarks. They should be punctual in meeting deadlines. They should avoid even subtle biases that relate to institutions, geography, race, and gender.


Policies and Guidelines

Institutions have little to say regarding peer review except in cases where scientific or other forms of professional misconduct are alleged. Those with a stake in the process are instead granting agencies and publishers. Examples of procedures and guidelines they provide are these:

NOT-OD-14-073: Maintaining Confidentiality in NIH Peer Review:

NIH Conflict of Interest Rules:

Cell Press Information for Reviewers:

PNAS Ethical Responsibilities of Reviewers:


Case Studies

Access to case studies requires a PennKey. They are available here.



Two textbooks provide excellent discussions of data acquisition and management. Both are electronically accessible through the Biomedical Library. These are:

Scientific Integrity, F.L. Macrina, 4th ed.
Responsible Conduct of Research, A.E. Shamoo and D.B. Resnick, 3rd ed.

Beyond the links provided in 'Procedures and Guidelines,' the Committee on Publication Ethics (COPE; can be quite useful. COPE provides over 500 cases dealing with authorship, plagiarism, duplications, corrections, and – important for the current module’s coverage – conflict of interest and peer review in general.