When The Music Stops: Alcohol and Evidence in Workplace Investigations

Alcohol and work events have a long and uneasy relationship. While end-of-year functions, team drinks and celebration events are intended to acknowledge staff contributions and build morale, they also present heightened conduct risks. From a workplace investigations perspective, incidents arising from alcohol-fuelled events consistently give rise to some of the most complex and sensitive investigations, often involving blurred professional boundaries, impaired judgement and competing accounts of what occurred.

Compounding this complexity, these investigations often commence well after the event, requiring investigators to contend not only with the passage of time but also with the potential effects of alcohol on perception and memory at the time the events occurred.

An investigator’s task is not to moralise alcohol consumption, nor to discount evidence simply because alcohol was involved. Rather, it is to undertake a careful and disciplined evaluation of how alcohol may have affected memory, observation and the interpretation of events, and to consider the extent to which those effects bear upon the reliability and probative value of the evidence as a whole.

When and how should alcohol consumption be considered?

A critical starting point is recognising that alcohol consumption does not of itself undermine a complaint, a response, or a witness account, nor does intoxication absolve a person of responsibility for their conduct.

However, alcohol will often be relevant in assessing:

• the reliability of a person’s observations and perception of events at the time they occurred;

• the integrity of memory formation with respect to those events;

• the consistency and reliability of subsequent recall; and

• the probative weight that can properly be attributed to an account when making findings.

Reliability, not credibility, is often the real issue

In alcohol-related matters, investigators often face the central question not of whether a person is being untruthful, but of the extent to which their evidence is reliable. Even when a person appears genuine, candid, and detailed, investigators must consider whether alcohol consumption at the relevant time may have affected the quality of the evidence provided.

This assessment is necessary because perception, memory formation and recall are inherently fallible, and alcohol can significantly heighten those limitations in ways that are not always apparent from the account presented. A person may appear coherent, articulate and confident, yet have formed an incomplete, distorted or fragmented memory of events. In such circumstances, the question is not whether an account should be accepted or rejected outright, but how much evidentiary weight it can properly be afforded when making findings, particularly where corroborating evidence is limited or absent.

Asking the right questions to assess evidentiary weight

In most cases, objective measures of alcohol consumption will be unavailable or limited, requiring investigators to rely on careful and appropriately framed questioning of participants to assess the impact of alcohol on the evidence. The aim of these questions is not to cast judgment but to obtain information that assists in evaluating the reliability of an account.

Examples of appropriate lines of questioning may include:

Alcohol consumption

• Can you tell me what you drank during the event, and approximately how many drinks you had?

• Over what period of time were you drinking?

• Do you recall when you had your first and last drink?

  
  

Context and mitigating factors

• Did you eat food during the event? If so, when?

• Were you also drinking non-alcoholic beverages?

  
  

Self-perception at the time

• How would you describe how you were feeling during the event?

• At any point, did you feel affected by alcohol? If so, in what way?

  
  

Memory and recall

• How clear is your recollection of the events now?

• Are there any parts of the evening that you find difficult to recall or are uncertain about?

• How did you feel the following day?

  
  

Reflective assessment

• Do you consider that alcohol may have affected your observations or memory of events in any way?

• Is there anything about the environment or circumstances that you think influenced your recollection?

  
  

Where appropriate, comparative tools may assist. For example:

• If you were to rate how affected you felt by alcohol on a scale of 0 to 10, where would you place yourself at different points during the event?

  
  

Importantly, these questions should be asked consistently and without judgment. Their purpose is to enable the investigator to contextualise the evidence and determine the weight that can reasonably be attributed to it, rather than to challenge or undermine a participant’s account.

Assessing Evidentiary Weight

When alcohol consumption is a relevant factor, it is important that an investigator does more than simply note its presence. The assessment should clearly demonstrate how information obtained about alcohol consumption has been considered when evaluating the reliability and weight of the evidence. Articulating this reasoning is critical to ensuring transparency, procedural fairness and defensibility, particularly where findings depend on the relative weight afforded to competing accounts. The examples below illustrate how an investigator might expressly record that assessment.

Example 1: Alcohol as a material factor

The available evidence indicates that [Person A] consumed approximately eight to ten alcoholic drinks over a period of three hours and later identified some uncertainty in recall. This is consistent with witness observations that [Person A] appeared increasingly affected by alcohol as the evening progressed. Having regard to the quantity and timing of alcohol consumption, I consider [Person A]’s alcohol consumption to be a relevant factor in assessing the reliability of their evidence.

By contrast, [Person B] reported consuming two to three alcoholic drinks over the course of the event, alongside food and non-alcoholic beverages, and advised that they were driving and therefore limited their alcohol consumption. [Person B]’s account of the relevant interaction remained consistent across interviews and was supported by contemporaneous text messages. In these circumstances, I accept [Person B]’s account as the more reliable version of events.

Example 2: Alcohol forming part of the context, but not a material factor

Both [Person A] and [Person B] acknowledged consuming alcohol during the end-of-year function. The evidence indicates that their consumption was moderate, occurred over an extended period, and was accompanied by food. Neither reported feeling affected by alcohol at the time of the interaction in question, and there is no other evidence indicating that alcohol should be taken into account when assessing their evidence.

Example 3: Alcohol limiting the findings

The evidence indicates that after approximately 10:00 pm, [Person A] consumed a substantial quantity of alcohol over a short period, reporting approximately six to eight additional drinks, including spirits. [Person B] reported consuming approximately four to five additional drinks during the same period, primarily beer. This is consistent with witness evidence that both appeared increasingly affected by alcohol as the evening progressed.

The accounts provided by [Person A] and [Person B] in relation to interactions during this period differ in material respects and contain areas of uncertainty. Having regard to the quantity, type and timing of alcohol consumption, and the witness observations, alcohol is a relevant factor affecting the reliability of the evidence for this period. In the absence of corroborating evidence, I am unable to determine, on the balance of probabilities, what occurred during this period.

Conclusion

Alcohol does not absolve conduct, nor does it automatically undermine evidence. Its relevance lies in how it affects what can be safely concluded from the available evidence.

For investigators, the challenge is to move beyond simplistic assumptions and instead engage in a careful, structured assessment of reliability and weight. Doing so strengthens both the integrity of the investigation and the defensibility of its outcomes, particularly in matters arising from work-related social events.

Matters involving alcohol, impaired memory and competing personal accounts are often among the most complex and sensitive workplace investigations. They require careful planning, experienced judgment and an approach that is demonstrably independent and procedurally fair.

Riskwise Consulting supports organisations in navigating these challenges through independent, trauma-informed, and legally defensible investigations, particularly when matters arise from work-related social events, involve senior employees, or present heightened regulatory or legal risk.

Author: Riskwise Director Matt Truelove is a highly experienced investigator and workplace consultant with extensive experience leading complex investigations as a former Detective and Senior Investigator in the Australian Public Service.