He use of research-based evidence has been promoted during recent years, due to the increasing development of evidence-based medicine,and it has been reported that transferring the concept of "evidence-based" from clinical to public health practice has not been as straight forward as expected.Much research-based evidence for supporting public health recommendations has come from studies whose evidence has been qualified as being low or very low quality in the medical hierarchy based on classic evidence and the grading of recommendations, assessment, development and evaluation (GRADE)approach. This paper was aimed at presenting two methods of rating evidence, as well as their limitations and applications as public health decision-making tools.