Delphi is a powerful technique used to seek answers to appropriate questions. The purpose of this paper is to provide an overview of the Delphi technique as a research method. This paper discusses the scientific merit of the Delphi technique by investigating on 41 studies of Journal of Agricultural Education from 1981 to 2013, and 2 studies of Journal of Agricultural Science and Technology. The results showed that there is no general agreement on using indexes in different rounds of Delphi technique; however, according to the frequencies of using indexes in different studies, the following suggestions are presented. The favourable number of panel of experts is between 10 to 20. Purposive sampling method is used for selecting the panel members. Usually a three rounds of Delphi method is used. One question is designed in round one. Mean and standard deviation indexes are used for passing from round two to round three and agreement level of 70 present is used for achieving expert's consensus in round three.