What a GREAT question, John! Exploring that might end up as a blog post itself.

When I was an HR manager, and me and the managers I worked with tried to put our fingers on what makes someone inspiring (for instance), I tried to help them break down, "I know it when I see it."

Does it look like people coming to a person spontaneously, to ask for advice? You could say that coffee shop employee (in my post) gave evidence that I was inspiring (to him) because he asked me for some directly :)

I'm reminded of those old EF Hutton TV commercials. (I am SO dating my age now...) The setting might be a loud, crowded restaurant, but when the EF Hutton rep began to speak, everyone hushed to hang on every word. In everyday life, would that mean listeners expect to be inspired? It could mean a number of things, but may be evidence of an ability to be inspiring.

Without conducting a study (maybe there is one out there), I don't know, but I do look for how other people respond to the person in question when I am looking for evidence of teamwork, ability to gain cooperation, and inspiration, for instance -- those things that seem difficult to measure.

You are reminding me of the book, Credibility, by Kouzes &amp; Posner. I'll bet they can answer your question better than me. Going to have to look that up today.  Thanks for the thought-provoking question, John.