Don't necessarily need to have a Ph.D. A professor of history once published a paper saying "No Irish Need Apply" signs were a myth. A 14 year old found counterexamples, and did a good enough job to get the takedown published.

https://www.independent.co.uk/news/world/americas/rebecca-fried-the-14yearold-student-who-outwitted-a-college-historian-10437603.html