Something anecdotal has to do with anecdotes — little stories. Anecdotal evidence is based on hearsay rather than hard facts.

People like to share stories about things that happened to them, or that they heard about, to make a point. That kind of talk is anecdotal: based on small, personal accounts. Anecdotal stories are helpful when you’re trying to give an example of something, but there's a downside to anecdotal information: since it’s not based on facts, you never know if you can totally trust it. So it's best to go beyond the anecdotal and get more solid information.

Definitions of anecdotal
  1. adjective
    having the character of an anecdote
    anecdotal evidence”
  2. adjective
    characterized by or given to telling anecdotes
    anecdotal conversation”
    “an anecdotal history of jazz”
    synonyms: anecdotic, anecdotical
    communicative, communicatory
    able or tending to communicate
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