Imagine noticing a mistake at work but hesitating to mention it. Perhaps you are worried about looking incompetent, upsetting your manager or being labelled difficult. That hesitation sits at the heart of psychological safety: whether people feel able to ask questions, raise concerns and admit mistakes without fear of embarrassment or punishment.

Leaders are often encouraged to create this kind of environment. The argument sounds straightforward: supportive leaders help people feel safe, and people who feel safe work more effectively. But how strong is the evidence behind that claim?

A new paper by our CBISS theme co-leads Geshwaree (Aartee) Huzooree and Melina Doargajudhur and colleagues, working with Corine de Ruiter and Vincent Dutot, examines this question. Published in The Leadership Quarterly, their review looks closely at what existing research can tell us about leadership, psychological safety and work outcomes.

The team reviewed 47 research articles published between 1990 and January 2026. Their aim was to assess whether the studies could establish cause and effect.

That distinction matters. If employees who describe their managers as supportive also report feeling safer and performing better, these things may be connected. However, this alone cannot establish that the manager’s behaviour caused the improvement. Other factors, such as working conditions, team relationships or previous success, could help explain the pattern.

The review found that none of the studies established the full causal chain from leader behaviour, through psychological safety, to better work outcomes. Some experiments provided partial evidence that changing leader behaviour could influence psychological safety. But they did not establish that psychological safety itself then caused better outcomes.

Another concern was how leadership was measured. In 82% of the review’s coded entries, researchers relied on employees’ ratings of their leaders. These ratings capture employees’ experiences, but they can mix what a leader actually does with how employees interpret that behaviour. This makes it difficult to identify which specific actions produce which effects.

So, what can we learn?

First, we should be careful about promises. The findings do not show that psychological safety is ineffective. They show that the research reviewed cannot yet confirm or refute the full explanation often used to support claims about improved performance.

Second, organisations need to be specific about leadership behaviour. “Be a supportive leader” is broad advice. Asking how a manager responds when someone raises a concern gives us something more concrete to examine. The review calls for research that separates observable actions from people’s judgements about those actions.

Third, leadership development needs thoughtful evaluation. A positive survey after a training session cannot, by itself, show that the programme improved performance or explain how any improvement happened. The authors recommend stronger experiments, clearer measures and studies in real workplaces to test each part of the proposed relationship.

For anyone managing people, the paper offers a useful question to ask when presented with a confident claim: what evidence shows that this particular action produces the promised result?

Through this work, our CBISS team encourages a more careful conversation about leadership and workplace improvement. Creating opportunities for people to speak openly deserves serious attention. Understanding how leaders can achieve that, and what follows from it, requires evidence we can trust.

Read the paper: A systematic and causal review of the link between leader-driven psychological safety and work outcomes.