First, there is corroboration. Ford’s therapist’s notes in 2012, provided to The Washington Post, generally record her account of the attack. To believe that this is a made-up tale to prevent Kavanaugh’s confirmation, Ford would have had to plant the seeds of this story in 2012. That makes no sense.
Second, while not determinative, the fact that Ford passed a polygraph administered by a former FBI agent lends credence to her claims. Polygraph exams are inadmissible in court because they are not always reliable, but the FBI and other law enforcement agencies frequently use polygraph tests to assess the credibility of witnesses and defendants.
In addition, consider the motives of Ford, who by all accounts is not a particularly politically active person, to go public with allegations of sexual assault. It appears that she did not want to speak publicly at all, but that reporters discovered her identity and pursued her. Ford knew that she would be personally attacked in front of her children, colleagues, students and friends. There is no reasonable explanation for why she would subject herself to such humiliation other than the reason she has given: that she felt she had a duty as a citizen to speak up.