Which factor is often considered during the ethical review of research involving human subjects?

The informed consent of participants is a fundamental ethical requirement in research involving human subjects. This process ensures that participants are fully aware of the nature of the research, including any potential risks, benefits, and the opportunity to withdraw at any time without penalty. Informed consent is crucial because it respects the autonomy and dignity of individuals by allowing them to make educated decisions about their participation.

Ethical review boards focus on informed consent to ensure that participants are not coerced or misled about the research. They assess whether researchers have provided clear and comprehensive information that allows individuals to understand what their participation entails. This protects participants and helps to maintain the integrity of the research process.

The other factors mentioned, such as the cost of research materials, adequate funding sources, and the length of the research proposal, do not directly pertain to the ethical treatment of human subjects. While they are practical considerations within the research process, they do not address the core ethical obligations to protect participants and ensure their informed and voluntary participation.