Up-to-date information for employers on topics and issues that may affect workplace operations. The posts are current as of the date of the posting.


by Jennifer Shaw and Lisa Buehler | The Daily Recorder | August 12, 2019

Employers must take both preventive and remedial action to stop unlawful discrimination, harassment, and retaliation at work.  An internal investigation is a critical tool to help fulfill these obligations. 

The facts underlying workplace complaints are not always easy to determine.   Investigators at times must find facts when versions of events conflict, or when there are no witnesses, except the complainant and accused.  To increase investigations’ effectiveness in difficult situations, investigators should understand the role of credibility, as well as the burdens of proof involved.

Evaluating Credibility

Investigators may resolve factual disputes by evaluating credibility factors, to assess which witness account(s) is or are the most reliable.  No one factor is determinative. The examples below are not exhaustive.

Motive to lie.  The accused may have a motive to lie. However, a complainant facing discharge may fabricate allegations about his supervisor to forestall disciplinary action.  The complaint’s timing and previous discipline may be relevant. 

Inherent plausibility.  If a witness’s account of events appears unlikely, an investigator may consider that factor.  Investigators also must remember  implausible does not necessarily mean impossible.

Corroboration or lack thereof.  An investigator may find information that corroborates a witness’s account.  Electronic data may corroborate a claimed communication, for example.  A remark to a co-worker shortly after an incident also may be evidence of corroboration. A lack of corroborating evidence also may be significant.

History of conduct. An investigator may consider an accused employee’s history of conduct in evaluating credibility.  Information about an employee’s history may be found in personnel records, or gleaned from other witnesses.   

Opportunity and capacity to hear or observe.  Similar to the plausibility factor, investigators should consider whether a witness actually was able to hear or see the conduct the witness described. A witness who embellishes based on what he or she claims to have witnessed, or who relates second-hand information as fact, may undermine his or her own credibility.

Reputation for honesty and deceit.  Investigators may rely on information about an employee’s reputation for honesty or deceit as a factor in assessing credibility.   This factor can be tricky, however, and should not be used as a substitute for actual fact finding.

Consistent/inconsistent statements. Employees that change their statements over time or give inconsistent statements to other witnesses may be deemed less credible than witnesses that give consistent statements. At the same time, investigators may consider factors that might make it difficult for witnesses to remember.  An employee who has experienced trauma in the past, for example, may find it difficult to recount events that triggered that trauma. 

Weighing Credibility Factors

Typically, investigators evaluate a number of different factors to determine which witness is more credible. Rarely will every credibility factor apply in an investigation. At times, investigators can rely on a single credibility factor, such as corroboration, in making findings.      

To make factual findings, most investigators list the allegations at issue and what each witness said about the allegation.  They then apply all relevant credibility factors to the witnesses and determine which witnesses are more credible.  In doing so, the investigator can determine where the weight of the evidence lies and make the appropriate factual finding. 

Evidentiary Standard for Investigations

An employer’s internal investigation of alleged misconduct, including discrimination or harassment, does not involve the same evidentiary standards as a trial.  However, the quality of an investigation may be scrutinized if there is a legal proceeding challenging an employment decision that involves an investigation.

The employer has broad latitude to discipline or discharge an accused wrongdoer who is employed “at will.”  Little to no “evidence” of wrongdoing is required.  On the other hand, employers must take greater care when the right to discipline or discharge is limited by an employment contract, collective bargaining agreement, or civil service rules.  The wrongdoer may claim the investigator’s conclusion was based on insufficient evidence, or poorly supported conclusions.

Management also should apply reasonable standards to avoid discrimination or retaliation claims by the accused. In Mendoza v. Western Medical Center, Santa Ana, for example, the employer discharged two employees, each of whom complained of harassment by the other. After investigating, the employer was unable to make a factual finding in favor of either employee’s version. A jury later awarded a six-figure verdict to Mendoza, the subordinate employee who lodged the initial complaint, based on retaliation for reporting harassment.

Complainants, too, may challenge findings. A finding that misconduct did not occur may be the subject of litigation, particularly if the complainant alleges the wrongdoer repeated the misconduct after the initial investigation.

As a matter of good practice, investigators should find facts based on a “preponderance” standard; i.e., that it is more likely than not that a fact is true.  A fact-finder will apply the same standard at trial or arbitration.  The investigator justifies each factual finding based on reasonable conclusions, including witness accounts, documents or other evidence, and credibility.


Employers must resist the temptation to throw up their hands and declare an investigation “inconclusive,” even in the proverbial “he-said/she-said” situation.  Failure to reach a conclusion makes it difficult or impossible to take the remedial action required by law.  More importantly, the dispute that led to the investigation remains unresolved, potentially leading to further conflict or claims.

Investigators may use credibility factors to help “break the tie,” when evidence otherwise would be inconclusive.  Proper documentation of credibility assessments, the bases for findings, and efforts to obtain other evidence, are essential to support findings when the verifiable facts are unclear.