The word you are looking for is anecdotalanecdotal.
(of an account) not necessarily true or reliable, because based on personal accounts rather than facts or research.
Anecdotal (adj): (of an account) not necessarily true or reliable, because based on personal accounts rather than facts or research.
Example: Historic accounts of this era give no indication of any negative impact to fish populations and in fact, anecdotal accounts reflect quite the opposite.
adjective. 1(of an account) not necessarily true or reliable, because based on personal accounts rather than facts or research. 'Historic accounts of this era give no indication of any negative impact to fish populations and in fact, anecdotal accounts reflect quite the opposite.[Lexico]