Providing a model to support the decision to select the most influential influencer in marketing campaigns on the Instagram social network.

With the advent of digital marketing and the subsequent emergence of social networks such as Facebook and Instagram, as well as the emergence of entities called influencers on these networks, numerous subcategories have arisen to optimize marketing activities with the purpose of having a larger, more effective, more targeted audience aiming at lowering the cost of advertising for businesses and obtaining greater efficiency. Influencer marketing is a branch of marketing that identifies and focuses on a specific person or a particular style of society and then observes potential audiences to lead other marketerschr('39') activities such as defining methods and markets, selecting the right target influencers, how to properly convey the message and attract the target audience in order to reach more efficiency and increase in the value of brands, businesses and products / services. The purpose of this study was to present a decision making model for selecting the most effective influencer(s) out of the existing influencer community in the  case study, Instagram social network, for the product / service being marketed. The criteria for identifying influencers in the present study were obtained by collecting those criteria that were studied sporadically in other studies previously. The data collection tool was a standard Likert 5point scale questionnaire in which these criteria were purposefully examined through distribution among100 experts in the relevant areas of the research subject, and were analyzed through Fuzzy Delphi Method. Content validity was used to verify its validity and Cronbachchr('39')s alpha coefficient was used to measure the reliability of the questionnaire. The reliability of the questionnaire was higher than 0.8 which is scientifically accepted. The weights of the final criteria were then determined for each of the five proposed products/services by SWARA Method. Finally, with those measurements, each criteria was individually assessed for 14 persons out of the community Instagram influencers using Multi-Criteria Decision Making (MCDM). The analysis showed a positive and significant relationship between the selected influencers and the proposed product / service.