With recall bias the historical information provided by a subject is not accurate. Usually the problem relates to memory and not an intent to mislead.
The subject may:
(1) fail to remember
(2) remember some things better than others
Factors that may contribute to recall bias:
(1) length of time since the event
(2) mental status of the subject now
(3) mental status of the subject in the past
(4) medications that interfere with cognition being taken in the past
(5) medications that interfere with cognition being taken at the time of the interview
(6) injury to the central nervous system since the event
(7) prompting by the interviewer
(8) wanting to be approved by the interviewer
(9) how dramatic an event was relative to other events
(10) exposure to media sources
(11) how much effort the subject makes to recall
(12) emotional state (anger, guilt, fear, confidence, etc)
(13) availability of records or notes to aid memory
(14) unaware of an exposure or events
