Every organisation has them. Unspoken rules. Silent judgments. Beliefs that nobody questions because they have always been there. Assumptions about who is a natural leader, who works hardest, who speaks for the room, and who should stay quiet. These assumptions do not announce themselves. They sit quietly inside hiring decisions, performance reviews, meeting dynamics, and promotion cycles, shaping outcomes in ways most teams never stop to examine.
An assumption is a belief you treat as fact without testing it. In the workplace, assumptions tend to cluster around identity, background, and perceived competence. They emerge from familiarity, from pattern recognition shortcuts in the brain, and from organisational cultures that reward certain types of people while quietly sidelining others.
The problem is not that people are making assumptions maliciously. Most are not. The problem is that unchallenged assumptions compound over time. A manager who assumes a working parent is less committed to a project will not put them forward for a stretch assignment. That person misses a development opportunity. Their career stalls. And nobody ever has a conversation about why.
One of the most persistent assumptions in professional environments is that confidence signals competence. People who speak assertively, take up space in meetings, and volunteer opinions freely are often perceived as more capable than those who are measured, reflective, or reserved.
Research from Columbia Business School found that people who display confidence are rated as more competent regardless of their actual ability. This creates an environment where the loudest voices consistently win resources, visibility, and advancement, while quieter contributors with equally strong or stronger skills are overlooked.
This connects directly to how organisations think about diversity in leadership – the faces at the top of most organisations still tend to reflect a particular archetype of what a leader looks, sounds, and behaves like.
“Cultural fit” is one of the most overused and underexamined criteria in hiring. When a hiring manager says someone is not a cultural fit, they are often describing a person who does not resemble the existing team in style, background, or communication approach.
A study by Lauren Rivera at Northwestern University found that elite professional service firms in the US heavily weighted cultural fit during hiring, and that this judgement often boiled down to shared leisure interests, educational pedigree, and similar upbringings. The result was systematic exclusion of candidates from different socioeconomic, cultural, or educational backgrounds, regardless of their professional capability.
Cultural fit, as typically applied, does not measure values alignment. It measures similarity. And similarity is not a performance predictor. It is a bias amplifier.
Remote workers, part-time employees, and those with caring responsibilities are frequently assumed to be less available, less ambitious, or less serious about their careers. This assumption has intensified since the shift to hybrid and remote working models.
For organisations working to build inclusive workplace policies, this is a foundational gap. If flexibility is offered in theory but penalised in practice through reduced visibility and fewer development opportunities, it is not actually inclusive.
Studies consistently show that ambition is read differently depending on gender. A 2022 McKinsey and LeanIn.org Women in the Workplace report found that women are still significantly underrepresented in senior leadership, and one of the key drivers is that ambition in women is more likely to be labelled negatively or treated with suspicion than the same behaviour in men.
Women who advocate for themselves are frequently described as difficult or aggressive in ways that men making identical requests are not. Women who take up less space are assumed to be less interested in advancement. Neither assumption is accurate. Both limit who gets ahead.
The same report found that for every 100 men promoted to manager, only 87 women are promoted. This gap, known as the broken rung, begins at the first step into leadership, and assumptions about who is leadership material are central to why it persists.
Seniority and experience are often treated as synonymous with insight and correctness. Junior team members or those new to an industry frequently have their ideas deprioritised or filtered out before they reach decision-making conversations, even when those ideas challenge processes that have stopped working.
Google’s Project Aristotle, which studied what made teams high-performing across hundreds of internal teams, found that psychological safety – the ability to speak up without fear of ridicule or punishment – was the single strongest predictor of team effectiveness. Psychological safety is directly undermined when the assumption holds that more senior voices are automatically more valid.
Individual assumptions rarely exist in isolation. They stack. A hiring assumption leads to a homogenous team. A homogenous team develops a narrow definition of cultural fit. That narrow definition reinforces the next hiring decision. Over time, the organisation believes it is meritocratic because everyone in it looks and thinks alike – which confirms the original assumption.
This is not a coincidence. It is a cycle. And it is why addressing unconscious bias cannot be a one-off training session. It requires structural intervention at the points where assumptions translate into decisions.
Replacing informal judgment with structured processes is one of the most evidence-backed ways to reduce assumption-driven decisions. Structured interviews, standardised scoring rubrics, and blind CV screening all reduce the room for assumptions to operate unchecked.
A study from the National Bureau of Economic Research found that structured hiring processes increased diversity in hiring outcomes by up to 50 percent compared to unstructured interviews, without compromising quality of hire.
Challenging assumptions requires that dissent be institutionally protected. This means creating explicit forums where team members can push back on prevailing thinking without professional risk. It means leaders modelling intellectual humility by openly updating their views when presented with new evidence.
If the only people who feel safe challenging the status quo are those with the most seniority, the organisation has not created psychological safety. It has created the appearance of it.
Many organisations assume they are more equitable than they are because they have not measured the gap between intent and outcome. Pay equity audits, promotion rate analysis by demographic, and qualitative listening exercises with underrepresented employees frequently reveal patterns that leadership had assumed were not there.
Organisations committed to data-driven DEI strategy treat measurement not as a box-ticking exercise but as the starting point for honest conversation about where assumptions are doing the most damage.
Unconscious bias training alone has a limited track record. A meta-analysis published in the Journal of Applied Psychology found that awareness training changes attitudes in the short term but does not reliably change behaviour. What does work is pairing awareness with structural accountability – making bias reduction part of how managers are evaluated, not just something they are invited to reflect on.
None of this works without leadership that visibly models the willingness to be wrong. When a senior leader in a meeting says “I assumed X – it turns out I was not right about that, here is what the data shows”, they do two things at once. They signal that being wrong is survivable. And they signal that evidence should override assumption.
This is uncommon enough to be notable when it happens. It should be standard.
Leaders who are serious about building psychologically safe teams understand that their own assumptions are not exempt from examination. They actively seek out feedback from people whose experience differs from their own. They create space for discomfort rather than smoothing it over with consensus.
The organisations that handle this best do not treat assumption-challenging as a periodic initiative. They build it into everyday practice.
That means hiring panels that include people from outside the immediate team. It means retrospectives that ask not just what went wrong but what assumptions shaped the decisions that led there. It means managers who are coached on the specific ways assumptions show up in performance conversations, not just trained to believe bias exists in the abstract.
It means asking the questions that feel uncomfortable: Who is consistently missing from this table? Whose ideas are getting credited to someone else? Who is being described by their personality rather than their work? Who has not been given a high-stakes assignment in the last 12 months, and why?
These are not rhetorical questions. They have answers. And the answers, more often than not, are shaped by assumptions that nobody has been asked to examine out loud.
Assumptions are inevitable. The human brain is a pattern-recognition machine, and in a workplace context, pattern recognition frequently defaults to the familiar. The goal is not to eliminate assumptions entirely – it is to build organisations where assumptions are routinely tested rather than automatically honoured.
The data is clear. More equitable organisations outperform. More inclusive teams make better decisions. More psychologically safe environments produce more innovation. These are not ideological positions. They are empirically documented outcomes.
The question is not whether your organisation has assumptions worth challenging. It does. Every organisation does. The question is whether it has the structures, the leadership, and the honest commitment to start doing something about it.
The Diverseek podcast aims to create a platform for meaningful conversations, education, and advocacy surrounding issues of diversity, equity, inclusion, and belonging in various aspects of society.