[Does impact factor influence the ethics of the instructions provided to journal authors?]

Verify whether a journal's impact factor is a mechanism that modifies the ethical requirements described in the instructions provided to authors of articles published in Brazilian medical journals.

48 selected journals were divided into two groups: impact-factor (n=24), and no-impact-factor (n=24). The number of ethical requirements was compared between both groups based on a specific research protocol, ranging from zero to six points, analyzing the presence of an approval by a research ethics committee; reference to the fact that the research follows the precepts of the Declaration of Helsinki and the rules of Resolution 196/96; use of an informed consent; information about the authors' conflicts of interest; and a request for registration of clinical trials in the Brazilian Clinical Trials Registry.

The average score of the impact-factor group was significantly higher than that of the no-impact-factor group (3.12 ± 1.03 vs. 2.08 ± 1.64, p=0.0121). When each ethical requirement was compared between the groups, there was significant difference only between the requirement of an informed consent and the disclosure of conflicts of interest (p < 0.05).

The impact factor is a determinant factor on the ethics included in the instructions to authors of articles in scientific journals, showing that higher-quality journals seek better-designed articles that are conscientious at the beginning of the research.