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How to identify toxic employees in the workplace

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Angry employee, representing counterproductive work behaviours.

What is toxic behaviour and why does it matter?

Nothing is more harmful to an organisation’s culture than toxic employees. Research shows that organisational culture is local, and the vast majority of an employee’s engagement and wellbeing comes from their immediate team (Cotton & Hart, 2011), so the presence of even one toxic employee in a team can have rippling effects on their colleagues and the wider organisation.

Toxicity can manifest itself in a range of Organisational and Interpersonal counterproductive work behaviours, from intentional impoliteness to others at work, bullying, to theft of organisation property and ignoring OH&S policies. This behaviour can result in a decrease in productivity, reduced engagement, low employee morale and increased turnover.

A 2015 study conducted by the Harvard Business School found that toxic employees can have substantial effects on employee productivity.

Of the approximately 60,000 employees surveyed who had been subjected to incivility in the workplace, 78% of respondents said that their commitment to their organisation declined, and 66% said that their overall performance declined (Housman & Minor, 2015). 

Not only do toxic employees diminish the productivity of fellow colleagues, but their toxicity can be passed on to colleagues in a kind of “contagion” effect . Employees who are exposed to or have contact with a toxic colleague are more likely to engage in toxic behaviour themselves. Research conducted by Cornerstone On Demand reported a 47% increase in the likelihood that a person would engage in toxic behaviours if they worked in a team with a high number of toxic colleagues.

There is also strong evidence for links between engagement in minor counterproductive work behaviours, such as incivility, and major counterproductive work behaviours, such as sexual harassment (Penney & Spector, 2005).

Sadly, toxic behaviour in the workplace appears to be an undeniable reality for many organisations and its costly impact on an organisation is clear. Understanding its root causes is powerful in preventing it occurring in the first place

So, where does toxic behaviour come from and what are the signs?

The answer is a mix of nature and nurture.

In 2013 SACS undertook a major study with Deakin University on counterproductive work behaviours. We surveyed in excess of 1000 working Australians and we asked them to confess to doing bad things – stealing things, bullying colleagues, taking sick days when they were not really sick, etc.

Because the survey was confidential people confessed to alarmingly high rates of these behaviours – way higher than people typically find in organisations because bad behaviours are massively underreported in the workplace. We also measured the values and personality profiles of all these people to see if we could find out how accurately values and personality predicted these bad behaviours. It turned out that we could predict the bad behaviours with 42% accuracy from their personality.


Personality is largely genetically determined and has a very significant impact on the likelihood of employees engaging in counterproductive work behaviours.

In particular, traits of Honesty-Humility, Conscientiousness and Extraversion are strongly linked to counterproductive work behaviours.

toxic employee angry man yelling into phone

Low Honesty-Humility. 

One marker of toxic behaviour is low levels of a personality characteristic called “honesty – humility”. This is a personality measure which indicates how truthful and trustworthy a person is, as well as whether they are arrogant or not. It seems that arrogant people have difficulty in being honest and truthful. This was a significant discovery for the world of psychology, because people who are low on honesty-humility have a number of marked risk factors – for instance they go to jail more often than people with high honesty-humility.

Employees with a personality disposition to honesty and modesty do less bad deeds than those who are arrogant and untruthful (Lee, 2012). People who have a natural tendency to anger are more likely to be aggressive towards others (e.g. Hepworth & Towler, 2004). Low Honesty Humility is also an indicator for the likelihood to sexually harass (Lee et al., 2003).

Low Conscientiousness. 

Another marker of a toxic employee is low conscientiousness, particularly the factors associated with self control such as the measure of “prudence”. People low in this tend to act more impulsively, rather than making decisions thoughtfully.

Low Extraversion

In SACS 2013 study in partnership with Deakin University, low sociability was found to be the strongest predictor of interpersonal counterproductive work behaviours.

This suggests that those who are more callous and anti-social in nature are more likely to engage in things like being impolite to others at work, ignoring, snubbing or excluding colleagues. Low extraversion by itself is not a concern, introverts can be excellent employees, but in combination with the factors above it can lead to psychopathy style behaviour.

Low Honesty Humility, Low Conscientiousness and Low Extraversion are personality characteristics that can be linked to ‘The Dark Triad’ . The Dark Triad is a cluster of three personality types which are closely interrelated – Psychopathy, Machiavellianism and Narcissism. A number of studies have linked traits of the Dark Triad to counterproductive work behaviours.

Cognitive Ability

In general work populations, employees with lower cognitive ability (which is largely genetic) tend to do more bad things than those with higher cognitive ability (Dilchert et al.,2007). Of course there are plenty of people with low IQ who are perfectly harmless, but over the course of multiple hires it is a risk factor for counterproductive work behaviour.


The factors above are largely genetic and research shows that they are the best indicators of likelihood to engage in counterproductive work behaviours. However, a person’s values, which are largely learnt, can also have an effect on the likelihood of negative behaviour.

While we could predict the bad behaviours with 42% accuracy from their personality, for values it was just under 18% accuracy. Values are nowhere near as strong a relationship as personality or IQ, but values can act as “protective factors” against the likelihood of violence.

Knafo, Daniel, and Khoury-Kassabri (2008) found that values could act as a moderating factor for violence.

For example, if a person was high in the value of “Conformity”, suggesting a respect for rules and a belief that being a rule abiding person is a good thing this served to reduce the likelihood that the person would commit violence. Similarly, if the person was low in the value of “Power” it made them less likely to seek to dominate others and therefore less likely to engage in extreme behaviours.

In short, values can be a protective factor against a personal inclination to negative or dangerous behaviours. I think the key point is to hire people with positive and benign personalities and it is also a good idea to test for the values necessary to help them manage anger or other extreme emotions.

The solution.

The easiest way to avoid toxic employees in your workplace is to identify them during the hiring process – and then choose not to hire them. The good news is that counterproductive work behaviours can be predicted by psychometric assessments and therefore can be avoided before they occur in the workplace. SACS psychometric assessments not only help to identify high performers, but also help to uncover the psychological makeup and toxic predisposition of candidates. Find out how you can conduct psychometric assessments for your hires.

SACS strongly recommends the use of counterproductive work behaviour testing in employment of people at all levels of seniority and in all vocational categories.

Staff reviewing assessments

Dealing with toxic employees. What if they are already in my workplace?

Evidently it is best to avoid hiring a toxic employee in the first place, but when it comes to dealing with toxic employees who are currently in your organisation, there are a number of approaches to managing counterproductive work behaviours. 

A suggested process is:

  1. Identification of the issue
  2. What is the evidence?
  3. Diagnosis. Psychometric assessments and/or 360-degree Feedback
  4. Prognosis. How likely is it that this can be turned around?
  5. Development of an agreed development plan
  6. Development of a clear accountability model
  7. Enactment of development plan with accountability measures
  8. Person moves up or down the escalation process – resolution.


A person’s experience or skill set can’t make up for the costly and damaging impact that toxic employees can have on your organisation. Identifying and avoiding candidates whose genetic predisposition indicates a high probability of engagement in toxic behaviour is the best way to safeguard your team and organisation.

Testing prospective employees on their personality, cognitive ability, values and counterproductive work behaviours will reduce your risks of toxic behaviours in the workplace. 

Reduce your risks of toxic behaviours in the workplace.

Access a FREE Psychometric Assessment Trial


Cotton, P. & Hart, P. (2011). ‘Positive Psychology in the Workplace’, Australian Psychological Society, 33(2).

Cornerstone On Demand. (2015). Toxic Employees in the Workplace Hidden Costs and How to Spot Them. 

Dilchert, Stephan; Ones, Deniz S.; Davis, Robert D.; Rostow, Cary D. Cognitive ability predicts objectively measured counterproductive work behaviors. Journal of Applied Psychology, Vol 92(3), May 2007, 616-627

Hepworth, W., and Towler, A. (2004) The effects of individual differences and charismatic leadership on workplace aggression. Journal of Occupational Health and Psychology, 9, 176-185.

Housman, M., & Minor, D. (2015). Toxic Workers. SSRN Electronic Journal. doi:10.2139/ssrn.2677700

Knafo, A., Daniel, E., & Khoury-Kassabri, M. (2008). Values as Protective Factors Against Violent Behavior in Jewish and Arab High Schools in Israel. Child Development, 79(3), 652-667. doi: 10.1111/j.1467-8624.2008.01149.x

Lee, K. (2012). The H factor of personality: Why some people are manipulative, self-entitled, materialistic, and exploitive—And why it matters for everyone. Wilfrid Laurier Univ. Press.

Lee, K, Gizzarone, M and Ashton, MC, Personality and the Likelihood to Sexually Harass. Sex Roles , 2003, Volume 49, Number 1-2, Page 59

Penney, L., & Spector, P. (2005). Job stress, incivility, and counterproductive work behavior (CWB): the moderating role of negative affectivity. Journal Of Organizational Behavior, 26(7), 777-796. doi: 10.1002/job.336

Andrew Marty

Managing Director at SACS Consulting

Andrew is a qualified psychologist who has over 25 years of human resource management consulting experience, including extensive senior executive search and selection experience.

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