11 April 2024 | Dr Jo Kandola

Does unconscious bias training work?

Unconscious bias training is a divisive topic that continues to be hotly debated. We weigh up the evidence and take an informed and objective look at what unconscious bias training involves and how effective it really is.

Unconscious bias training has probably received more media attention than any other DEI activity in recent years, with some polarising views emerging on its effectiveness. But what’s the real story behind the headlines?

What is unconscious bias training?

Unconscious bias training seeks to highlight and mitigate the impact of unconscious biases on our decision-making and behaviour. Unconscious biases differ from our explicitly held beliefs in that we’re not aware of them – and they may not actually reflect the beliefs we consciously hold – but they can still have a hugely negative impact on workplace processes and interactions. They can also negatively affect opportunities for the career development of people from minority and marginalised groups.

There are typically two types of unconscious bias training:

Training that focuses on a particular form of bias.

With this type of training, the structure follows the same format but the content, context and detail of the material changes depending on the particular area of bias under scrutiny. With regards to gender, for example, the training would look specifically at what drives gender bias, how it manifests itself, how gendered stereotypes can impact men, women, trans, gender non-conforming and non-binary people in the workplace, the impact of gender bias and what people can do to address it.

Training that focuses on how to reduce bias in a certain process.

Here, the training takes a specific workplace process, such as recruitment, development or promotion, and looks at the potential of bias to affect personal interactions and decisions and how to mitigate this impact at the various stages of the process.

Is unconscious bias training effective?


A thorough review of the existing research on unconscious bias training reveals both positive and nuanced findings. Studies such as that conducted by the Harvard Business Review suggest that when implemented correctly, unconscious bias training can increase awareness of biases, foster more inclusive behaviours, promote diversity in decision-making processes and increase representation of marginalised groups.

On the other hand, a 2020 report by the UK Government’s Behavioural Insights Team found that ‘there is currently no evidence that this training changes behaviour in the long term or improves workplace equality in terms of representation of women, ethnic minorities or other minority groups’. It also stated that there was emerging evidence of unintended negative consequences.

In practice, there is a huge variation in the degree, depth and competence in which each element of unconscious bias training has been covered in the research, as well as a vast variation in the nature and quality of the training itself, something that makes objective evaluation very tricky, since we are not comparing like for like.

Criticism of unconscious bias training

Let’s have a look at some of the most common arguments against unconscious bias training and see how they stand up.

  • ‘It doesn’t lead to a change in attitude to explicit beliefs’

This criticism completely misses the objective of the training. Unconscious bias training is about tackling unconscious, or implicit bias associations, not an individual’s explicit (or consciously held) beliefs. This is a bit like criticising toothpaste because it doesn’t work to straighten your teeth, rather than assessing its ability to keep them free from cavities.

  • ‘It doesn’t lead to implicit attitude change’

It ultimately comes down to how good the training is, and whether it’s based on solid behaviour-change methodology. There is in fact plenty of strong evidence pointing to implicit attitude change following unconscious bias training across a range of biases, as demonstrated by research into training around gender, race and LGBTQ+ inclusion. However, poorly designed training is unlikely to achieve the desired outcome, and with much of the unconscious bias training available focusing on raising awareness, with little emphasis on action, there will inevitably be many cases where it fails to achieve real, lasting change.

  • ‘Behaviour change doesn’t last after unconscious bias training’

A frequently cited meta-analysis of 426 studies found that ‘although there was a reduction in bias immediately after training (albeit a very slight reduction), this disappeared after time.’ This meta-analysis is one of the most commonly cited and looks impressive given the number of studies involved. However, a closer look at the 426 studies shows that these included alternative interventions for tackling unconscious bias, such as exposure to positive exemplars, implementation intentions and effortful processing – but not unconscious bias training.

  • ‘There is no impact on the representation of people from marginalised groups’

There is ample evidence – using control groups and experimental groups – to show that unconscious bias training does indeed lead to lasting change and positive impacts for marginalised groups. For example, one study on gender bias looked at the effectiveness of a gender bias workshop carried out at a US university. The study used an experimental group that undertook a 2.5-hour workshop on gender bias, as well as a control group that received no training whatsoever.

The results showed that when over 25% of the faculty undertook the training, there was an increase in action to promote gender equality. Staff surveys also showed that staff felt that they fit in better, felt more valued and had greater comfort in raising conflicts in scheduling obligations. So not only was there measurable behaviour change following the training session, but those typically on the receiving end of gender bias noticed the change and felt its impact in the workplace.

Two years after this research, the same researchers went back and explored the impact of training on the progression of women. They found that while the proportion of women hired by the control department (who received no training) had remained stable, the proportion of women hired by departments who had participated in the unconscious bias training had increased by 18% over the same period.

  • ‘It has an adverse impact on the representation of marginalised groups’

The research most commonly cited for this argument states that a study of 829 companies over 31 years showed that bias training had no positive effects in the average workplace. On closer examination, however, a much more complex picture arguably emerges. The researchers looked at several interventions, one of which was diversity training, but they did not look specifically at unconscious bias training.

This diversity training was found to have increased the percentage of Hispanic women and black men at senior levels, but it also hurt black women. What is hard to establish is the exact focus of the diversity training itself. It mentions stereotypes and bias training but gives no exact detail on the type of training being used across the 829 companies, or how it varied. So it would be wrong to conclude from this study that unconscious bias training has an adverse effect on marginalised groups.

How to get results from unconscious bias training


Our research at Pearn Kandola has identified the five essential components for effective unconscious bias training that brings about lasting behaviour change.

  • It has to be focused

Unconscious bias training can’t be generic and it shouldn’t talk about unconscious bias in purely theoretical terms. It needs to have a specific, practical focus, and there needs to be an alignment between the training, the actual bias being targeted and the expected behavioural outcomes for individuals.

  • It needs to be relevant

People need to see that the training is relevant to them and understand the personal benefits that tackling their unconscious biases will bring, whether that’s better professional relationships, an enhanced ability to communicate with people or better decision-making capabilities.

  • It needs to provide personal insights and feedback

You can’t just tell people about bias. They need to have insight into their own biases and how they might play out in the workplace, and they need to be shown exactly how to address them. All of the effective training measured in successful studies gave individuals personalised feedback and insight into their own biases.

  • It can’t be a one-off

Following their feedback, individuals need time to reflect on it. They need to consider what it means, try out new behaviours and analyse their impact. A continuous programme of training ensures that key messaging and best practice become embedded, and that people are supported on their inclusion journey.

  • It can’t exist in a vacuum

Unconscious bias training isn’t the silver bullet that’s going to fix everything. It needs to be endorsed from the top, supported by clear diversity and inclusion policies and delivered as part of a holistic and organisation-wide approach to DEI that genuinely strives to create an inclusive working culture.

A virtuous cycle of inclusion

Powered by psychology and a deep understanding of behaviour change, the Kandola+ Unconscious Bias programme provides learners with personalised insights, highlights their areas of strength and the areas which they need to work on and provides them with a tailored action plan, so they know exactly what they need to do to overcome their biases.

We know that our approach works.

An impressive 94% of our programme participants state that they know how to become more inclusive after having completed our training. Worth noting, too, is that impact studies show that these behaviours aren’t just restricted to those who have completed the training but are also being demonstrated by people in the wider organisation several months after the training has ended.

Contact us to learn more and find out how Unconscious Bias training from Kandola+ can help you achieve culture transformation at scale.