As Donald Rumsfeld famously said, "There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know."

He then added, "It is the latter category that tend to be the difficult ones." If you are unknowingly making hiring, managing and firing decisions based upon preferences you do not recognise you have, are you at risk of making discriminatory decisions?

What is unconscious bias?

Unconscious bias occurs when someone's behaviour or decision making is affected because of preferences based on another person's characteristics, experiences, or traits, without them knowing it.

Examples include a job applicant who has attended the same school as the interviewer, a manager who has the same ethnicity as a junior colleague or a teacher who is from the same area as a pupil. The person in the position of power tends to unconsciously treat these people more favourably than others.

There are, however, many different types of unconscious bias. These include:

  • Affinity bias – the tendency of one person to favour another who is similar to them. This is the most common type used to explain the concept and applies to all of the examples above.
  • Benevolent bias – a difference in treatment on the assumption that someone would prefer to be treated that way. The classic example is a manager who does not offer a new work opportunity to a parent so that they can spend more time with their children, regardless of what the parent actually wants.
  • Perception bias – when stereotypes associated with a particular group prevent an objective assessment of those belonging to that group. Taking the example of the parent above, the same manager would give the work to someone else on the assumption that a parent would not focus as much attention on the project as someone who did not have children.
  • The halo effect – when a person judges everything another does in a positive light because he/she likes them, regardless of their actual performance.

The range and seriousness of unconscious bias is broad and, in some cases, it can result in unlawful discriminatory behaviour.

Why is it so harmful?

Unconscious bias often rears its head in the employment context when disciplinary processes, promotions and job offers are being considered. For example, Government research has shown that people who applied for a job with a 'white sounding name' were 74% more likely to receive a positive response than those with an 'ethnic minority name'.

It is easier to understand (and therefore criticise) someone who treats another differently in a conscious pattern of behaviour than someone who treats another differently having not consciously considered their own behaviour and perceptions.

But the outcome for the victim of bias can often be the same, and unconscious bias can even be more harmful given the difficulty in identifying and addressing it.

Employers should therefore be wary of unconscious bias and take action to address it for three reasons:

  • Having a culture which is free of bias, be it conscious or unconscious, is the right thing to do. It will attract the top talent regardless of background, gender or ethnicity and project a positive brand for the business.
  • Unconscious bias can inhibit diversity at all levels. Research has consistently shown that having a more diverse management team has a direct positive link to financial performance.
  • There can be legal consequences for employers if unconscious bias creeps into the workplace, as shown in the case below.

Mr Aplin was a headteacher, and gay. In August 2015, he met two seventeen year olds via Grindr, and the three of them had sex. The app requires a user to certify that they are over 18 and Mr Aplin believed that this was the case with the two boys.

The police investigated and concluded that no criminal offence had been committed. Social services were satisfied that no child protection issue arose, but recommended that the school consider disciplinary action against Mr Aplin.

A local authority employee, Mr Gordon, was appointed as the investigating officer and presented a report to a panel of school governors, who concluded that Mr Aplin's employment should be terminated. Mr Aplin brought a tribunal claim, arguing that the disciplinary process and the termination of his employment were influenced by his sexual orientation.

The tribunal found that Mr Gordon's approach to the investigation and disciplinary hearing amounted to direct discrimination because of sexual orientation. He had included value judgments and hostile subjective criticisms of Mr Aplin in his report, but was unable to recognise his bias or offer any explanation for it.

The disciplinary panel had not given Mr Aplin an opportunity to review all the evidence used against him, ignored Mr Aplin's complaint that Mr Gordon was biased, and had decided that they were able to ignore the subjective elements of Mr Gordon's report, when in reality they could not distinguish between the objective and subjective elements.

However, it appeared that the governors (in breach of their own obligations) had effectively passed the decision to a local authority lawyer who was advising them and so the tribunal held that they had not discriminated against Mr Aplin.

The Employment Appeal Tribunal (EAT) upheld the tribunal's decision that Mr Gordon had directly discriminated against Mr Aplin, and found that the tribunal had been wrong to say the school governors had not directly discriminated against him too. At the very least, the tribunal should have considered why the governors effectively deferred their decision to the Local Authority lawyer.

The EAT also considered the actions of the local authority lawyer who was advising the panel. According to the EAT, the fact that he was not motivated by Mr Aplin's sexual orientation did not necessarily preclude a finding of discrimination, as his actions could have been based on "unconscious assumptions".

The EAT eventually concluded that his actions were non-discriminatory, but its comment in this context shows the risks arising from unconscious bias.

This case demonstrates that unconscious bias can influence decision making to varying degrees, and shows the risk of a superficially objective process which allows unconscious bias to influence decision-making.

How can employers address unconscious bias?


Managers and decision makers should be trained to identify and deal with unconscious bias. Training can take many different forms. A good place to start is with interactive training exercises which explain the concept of unconscious bias and give tips on how to address it.

Many employers already invest in this kind of training but often just to provide a whistle-stop tour of the concept. Ideally, training should include an opportunity for each decision maker/senior employee to identify unconscious biases and work on addressing these on an individual and ongoing basis.

At the very least, the aim for every organisation should be for all employees to be aware of unconscious bias, be alert to the harm it can cause and have some basic strategies to deal with it.

As the Aplin case shows, if decision makers are not aware of the way that unconscious bias can influence them when they are conducting a disciplinary investigation for example, there can be legal consequences.


Promoting an inclusive and diverse workplace is key to addressing unconscious bias.

The benefits from training and raising awareness are limited if, for example, employees do not feel able to call out bias when they suspect it is influencing a decision, or comment on the makeup of a management team if they feel it is too homogenous.

Initiatives in the workplace, such as an 'unconscious bias day' to raise awareness or a committee to focus on it, together with clear communications on the topic from management, can help to demonstrate that recognising and calling out unconscious bias in an organisation is supported.

A cultural shift like this will in turn help to reduce unconscious bias.

Recruitment and promotion strategies

Some employers use blind recruitment, which is designed to address unconscious bias by excluding personal details from the early stages of the application process, for example during first interviews. Excluded details can include name, age, and school attended. Organisations such as HSBC and the BBC regularly use this style of recruitment.

Taking this one step further, holistic recruitment techniques can also be used, which involve looking beyond qualifications to identify other factors, such as the standard of school attended and whether the applicant was privately educated or the first in their family to go to university.

By proactively considering factors which are likely to give rise to unconscious bias at an early stage of the process, employers can ensure that good candidates are not being overlooked and that their background is sufficiently factored in to the process.

Employers can also analyse their promotion process and assess the risk of unconscious bias creeping in.

For example, question whether all senior managers share similar characteristics and backgrounds. If so, consider why. Asking these kinds of questions is an important step in addressing unconscious bias and diversity more broadly in an organisation.