Ethical oversight is a critical requirement to conduct clinical research involving human participants and Institutional Review Board (IRB) and it is responsible to evaluate the ethical elements of a clinical research. However, there is no consensus on criteria for evaluating risks and benefits to human participants. Therefore, this article reviews the evaluation of risks and the potential benefits of a clinical trial using Multi-Attribute Utility Theory (MAUT) and suggests the incorporation of 5 levels of likelihood that risk event will occur for the standardisation of risk and benefit utility values.