The most common assumption that was found throughout the review of relevant literature was that the opinion of multiple persons is better than the opinion of one person. The Delphi method relies on the assumption that information gathered from a group is more valuable than that of individuals (Hyndman & Athanasopoulos, 2018). 

It is assumed that safety is within numbers, meaning that several people are less likely to make a wrong decision than an individual (Hasson et al., 2000).

Another assumption concerning the Delphi process is that all participants are assumed to have knowledge and experience that are equivalent to one another (Hua & Sandford, 2007; Altschuld & Thomas, 1991). It is important to take the knowledge and expertise of a participant into consideration when including them in a study to determine one's credibility within research.