The story-teller is the person (or the institution) that select and use a narrative relevant for guiding action. By doing so a story-teller endorses both the relevance of the story (in terms of framing of the issue) and usefulness (in terms of guiding action).
For more information: M. Giampietro (2017): Structuring the perception (qualitative) and representation (quantitative) of the nexus with new concepts and narratives. In: Report on Nexus Security using Quantitative Story-Telling. MAGIC (H2020–GA 689669) Project Deliverable 4.1.