Presumably, the decision must have seemed reasonable to the employer at the time. It was 2010, and Romeo Mendoza, a nurse and mid-level supervisor at Western Medical Center Santa Ana (known as Orange County Global Medical Center beginning in 2015), had filed a complaint alleging that one of his supervisors, Del Erdmann, had sexually harassed him on an ongoing basis. An internal investigation found that both Mendoza and Erdmann were complicit in the behavior, however, and the hospital fired both of them.

But after Mendoza sued Western Medical for wrongful termination, cracks began emerging in the quality of the hospital’s investigation. At trial, Mendoza’s expert testified that, among other things, the investigator had interviewed both Mendoza and Erdmann simultaneously; had failed to interview any other witnesses; and was not even a trained investigator (Mendoza’s and Erdmann’s supervisor investigated the matter). California’s Court of Appeal for the Fourth District likewise found fault with the investigation. “The lack of a rigorous investigation by defendants is evidence suggesting that defendants did not value the discovery of the truth so much as a way to clean up the mess that was uncovered when Mendoza made his complaint,” the Court wrote. “ …. [A] more thorough investigation might have disclosed additional character and credibility evidence for defendants to consider before making their decision.”

In California, employers must investigate employees’ complaints regarding discrimination, retaliation, or harassment. But the investigation must be a good one; as Western Medical found, mediocrity can create problems in subsequent litigation. Indeed, California’s Fair Employment and Housing Act (FEHA) requires a prompt, thorough and objective investigation whenever there is an allegation of discrimination, harassment, or retaliation.

Adverse Arbitration Outcomes

But FEHA and the threat of litigation in the private sector are not the only reasons why employers should ensure an investigation is sound. Public entities, which must provide employees with due process before resorting to termination or other types of discipline, also face potential risks with inadequate investigations, particularly when law enforcement officers are the subjects of disciplinary action. Municipalities across California and the country have repeatedly found that arbitrators are notorious for reversing termination and overturning disciplinary actions against police officers.

In fact, a study conducted by Loyola Law School Professor Stephen Rushin and published in the Vanderbilt Law Review in 2021 analyzed 624 arbitration awards between 2006 and 2020 from various law enforcement agencies across the country. Rushin found that arbitrators reduced or overturned police officer discipline in 52% of these cases. In 46% of cases involving termination, arbitrators ordered police departments to rehire previously terminated officers. And on average, arbitrators reduced the length of officer suspensions by approximately 49%.

Frequently, arbitrators found that the original discipline was excessive relative to the offense committed or compared to punishments received by other officers. In other instances, arbitrators cited insufficient evidence or procedural flaws in the investigation. Rushin further notes that “the high rate of disciplinary reductions or reversals by arbitrators on appeal may suggest that many departments are failing to conduct sufficiently robust investigations.”

Guarding Against Bad and Mediocre Investigations

In investigations ranging from private employment matters to law enforcement oversight, how do you guard against inadequate investigations? Here are four strategies to help ensure your investigation is robust enough to withstand scrutiny at trial or arbitration:

1. Include All Relevant Witnesses and Other Evidence

A robust investigation must take into account all pertinent witnesses and evidence, including:

• Witnesses with relevant information (even if obtained secondhand)
• Documents
• Data
• Emails and texts

It’s tempting to cut corners and neglect to interview a witness who may (or may not) have helpful information or to skip analyzing additional documents. However, by doing so, you risk settling for a substandard investigation that falls apart under scrutiny. For example, in Mendoza v. Western Medical Center, discussed above, the investigator only interviewed the two parties directly involved. This omission created problems when an additional witness testified at trial and lent credibility to Mendoza’s claims.

When in doubt, never exclude evidence or an interview. Answer any potential questions a third party might have about overlooked evidence. If an objective third party reading your report might ask, “What about ________?,” then that gap should be addressed before concluding the investigation.

2. Assess Witness Credibility

Witnesses may offer opposing versions of events and findings may depend on who is more credible. Especially in law enforcement agencies, do not assume, without evidence, that the officer is more credible. Assess credibility using these factors:

• Corroboration: Is there supporting evidence, such as witness testimony, documents, or contemporaneous notes that supports a party’s version of events?
• Consistent/Inconsistent Statements: Has the witness maintained consistency over time? Or has the witness’s version of events changed in various interviews or other communications?
• Capacity to Observe: Did the witness observe the events firsthand? How close was the witness to the event when it occurred?
• Past History and Pattern of Conduct: Does the respondent have a history of similar actions?
• Plausibility: Does the witness’s account logically make sense?
• Motive to Lie or Fabricate: Does the witness have a reason to lie? Might the witness’s version of events be skewed by bias or other motives?
• Reputation for Honesty or Deception: Does the witness have a history of honesty or fabrication?

Keep in mind that not all factors may apply in every situation, but generally, assessing these elements can significantly enhance your credibility analysis.

3. Effectively Analyze the Evidence

Investigators must go beyond summarizing the facts; their reports need to explain why their findings are justified. A well-reasoned analysis should:

• Cite specific witness statements, documents, and data supporting the conclusion
• Address contrary evidence and explain why it is insufficient to change the outcome
• Show logical reasoning in arriving at a finding

For example, if a respondent denies making an offensive remark, but multiple witnesses independently confirm it, the weight of evidence may support the complainant’s claim. Clearly articulating analytical steps strengthens the investigation’s conclusions.

4. Apply the Correct Burden of Proof

Workplace and administrative investigations typically use the Preponderance of the Evidence standard, meaning:

• The evidence must show that it is more likely than not that the alleged conduct did (or did not) occur. In other words, the evidence on one side outweighs—even if only slightly—the evidence on the other.
• This does not require proof beyond a reasonable doubt (the higher standard used in criminal cases).

Applying this standard correctly means considering all available evidence and determining whether, when weighed together, the allegations occurred. Circumstantial evidence can also play a role in this assessment.

In Closing

Conducting thorough and objective investigations is not merely a legal obligation but a critical component of maintaining workplace integrity and fairness. Employers must also ensure that their investigative processes are sufficiently robust to withstand scrutiny in litigation or arbitration. By including all relevant witnesses and evidence, assessing witness credibility, effectively analyzing the evidence, and applying the correct burden of proof, employers can significantly mitigate the risk of adverse outcomes.

Moreover, the commitment to diligent investigations reinforces an organizational culture that values truth and accountability. This practice not only protects the rights of all employees but also fortifies the organization’s reputation and operational efficacy. In a landscape where mediocrity in investigations can lead to severe repercussions, conducting good investigations is crucial.