Dr. Brian Richardson and Dr. Joseph "Joe" McGlynn recently published their manuscript "Constructing the heroic whistleblower: A social scientific approach" in Heroism Science, as part of that journal's special issue "Whistleblowers as Heroes." Using data from earlier studies into whistleblower's experiences, Richardson and McGlynn's article identifies five dimensions as significant for distinguishing heroic (vs. less heroic) whistleblowers. These five dimensions include motivation for blowing the whistle, complicity in the wrongdoing, level of risk involved, whether they affected change, and their willingness to blow the whistle again. Throughout their essay, Richardson and McGlynn include examples from actual whistleblowers.
The article is linked here: https://scholarship.richmond.edu/cgi/viewcontent.cgi?article=1039&context=heroism-science