The truth is, anecdotes are bad evidence. They are the experience of one person and aren’t repeatable, reliable or probabilistic (hello rule of three). Not to mention the fact that a person with an anecdote might have made an error in connecting it to the outcome. For example, someone might say, After I started my new nightly routine of bathing in the blood of unicorns, my skin cleared up. Perhaps they think so, but it could also have been a coincidence, or a consequence of getting more fresh air and exercise on all those daily unicorn hunts.
Though he was talking about life at the time, Macbeth’s Act 5 soliloquy comes to mind when I think about bad anecdotes.
“It is a tale / told by an idiot, full of sound and fury, / signifying nothing.”