Generally, the standard of proof used in workplace investigations is the “preponderance of the evidence.” Under this standard, the investigator determines what “more likely than not” occurred. Under the preponderance of the evidence standard, 50% weight “plus a feather” tips the scales of credibility one way or the other. Weight is assigned by applying nine well-established credibility factors: (1) the existence and degree of corroboration; (2) opportunity of the witness to observe events; (3) ability of the witness to remember; (4) possible corruption of memory due to scientifically-recognized psychological phenomena; (5) reputation for truthfulness; (6) plausibility; (7) motive of the witness to lie; (8) witness bias; and (9) demeanor when answering questions.
The “Nifty Nine” Credibility Factors
Credibility Factor #1: The Existence and Degree of Corroboration. The most important credibility factor is whether there is corroboration for a witness’s version of events and the strength of that corroboration. A competent workplace investigator digs for corroboration on both sides of the controversy. Corroboration typically comes from other witnesses or documents. A complainant whose story is corroborated by two other witnesses is usually more credible than the uncorroborated statements of the respondent.
One must also weigh the strength of the corroboration. If the two corroborating witnesses were close friends of the claimant and all three had recently been disciplined by the respondent, who was their manager, the power of the corroboration is diminished.
Suppose the corroboration of the potentially-biased witnesses was juxtaposed with documentary corroboration provided by the respondent from the employer’s official records—for example an email from the complainant to the respondent. In such a situation, the respondent’s documentary corroboration would likely be more convincing than the mere statements of the claimant’s good friends.
Credibility Factor #2: Opportunity of Witnesses to Observe Accurately. At a loud holiday party, a witness standing right next to someone who allegedly cracked a dirty joke is in a better position to observe than someone standing six feet away. If the two witnesses disagree as to what the respondent actually said, all other things being equal, the one who was closer to the respondent may be the more credible.
Credibility Factor #3: Ability to Remember. For example, alcohol consumption, and its effect on memory, is often a factor in assessing what actually occurred during or after office parties. Workplace investigators often seek bar and restaurant receipts in an attempt to determine who consumed which alcoholic beverages and how much was consumed.
Credibility Factor #4: Possible Corruption of Memory. Corruption of memory is different from inability to remember. Corruption of memory occurs when a witness has a clear memory of an event, but the accuracy of the memory has been tainted after the event due to various scientifically-recognized means, for example the witness discussing the event with other witnesses or reading media reports.
Credibility Factor #5: Reputation for Truthfulness. Workplace investigators may ask one witness about another witness’s reputation for truthfulness. A witness with a reputation for lying may have the balance of credibility tipped against them.
Credibility Factor #6: Plausibility. Workplace investigators will judge credibility according to which version of events seems more plausible. When I think about the factor of plausibility, I remember the criminal investigation where I live of a rape that occurred in a city park. The victim described her attacker as a Hispanic man who used a distinctive blanket, and wore clothes she could describe in detail. A short time later the police apprehended a man nearby who exactly matched the description of the woman’s attacker right down to the blanket in his car. In protesting his innocence, the man said that his twin brother, “Pedro,” who was dressed exactly like him, asked him to pick him up at the park, who had the blanket with him but accidentally left in it the car of the man the suspect. Needless to say, the police did not find the suspect’s explanation as plausible as the woman’s version of events. I always think of this as the “Pedro defense.”
Credibility Factor #7: Motive to Lie. In every investigation, both the complainant and the respondent could have a motive to lie. But all motives are not created equal. If the respondent is accused of conduct that would be criminal if proven, then the respondent has a huge motive to lie. The desire to stay out of jail is a great motive for a guilty person to deny guilt. If that is compared to a complainant who has no apparent reason to fabricate allegations against the respondent, then the balance of credibility may tip against the respondent.
Credibility Factor #8: Witness Bias. In the example stated as to Credibility Factor #1 above, the claimant’s two witnesses had a motive to lie in support of the claimant, who was their good friend.
Credibility Factor #9: Witness Demeanor. There are a variety of things most people think are reliable indicators of truthfulness or deceit such as looking the questioner in the eye, nervousness, combativeness, nervous ticks, and so on. However numerous scientific studies have repeatedly shown that these sort of demeanor clues are not very reliable indicators of truthfulness or deceit. Even polygraph tests, which scientifically measure breathing, pulse, and even sweating, are not deemed sufficiently reliable in science to be admissible in a court of law. Nevertheless, demeanor is something ordinary people use in everyday life to assess credibility, and workplace investigators may rely upon witness demeanor as well.
Attorney Gene R. Thornton is highly experienced in conducting workplace investigations of all types and is an Association of Workplace Investigators Certificate Holder (AWI-CH). Contact Mr. Thornton at Thornton Workplace Investigations, LLC for a free initial consultation for your next workplace investigation situation.