When a team is under stress, the reflex is to look at workload: hire, redistribute, push back deadlines. A new meta-analysis covering 60 years of role stress research points somewhere else. Across 515 studies and nearly 788,000 workers, role ambiguity (not knowing what is expected of you) did more damage to performance and engagement than heavy workloads. Conflicting demands drove burnout and resignations. Overload, the usual suspect, was not the main driver of either.

That changes where HR and leadership should put their effort.

What the research looked at

In 2026, a team led by Gargi Sawhney at Auburn University published a meta-analysis in the Journal of Vocational Behavior pulling together 60 years of research on three "role stressors":

• Role overload: more work than the time and resources allow.
• Role conflict: demands that pull in opposite directions. Two managers, two priorities, one person.
• Role ambiguity: not knowing what is expected, how success is judged, or what you are allowed to decide.

Most organisations lump these together as "stress". The study shows they are related but distinct, and that they hit different outcomes. The authors' conclusion is blunt: ambiguity "tends to be the most detrimental driver of employee and organizational outcomes".

Three stressors, three different costs

This is the part that matters for your operating results.

• Role ambiguity hits output. It was the most damaging stressor for most of the 14 outcomes studied, including job satisfaction, commitment and the extra effort people give beyond their job description. Of the drop in task performance linked to the three stressors, about 80% traced back to ambiguity. For work engagement, about 70%.
• Role conflict hits retention. It was the strongest driver of burnout, accounting for nearly half (47.5%) of the burnout effect linked to the three stressors, and the strongest driver of intention to quit.
• Role overload hits how people feel. Too much work weighed most on negative emotions and physical complaints. Real, but not the main lever on performance or turnover.

In plain terms: people who don't know what success looks like work hard on the wrong things, slowly disengage and stop going the extra mile. People pulled between competing bosses or priorities burn out and leave.

Why more headcount won't fix it

Overload has an obvious fix: more people, more time, fewer tasks. That is why it gets the attention. Ambiguity and conflict don't show up in a capacity plan. They show up as:

• work redone because the brief changed halfway,
• decisions bouncing back up because nobody knows who owns them,
• two teams optimising for goals that contradict each other,
• a strong performer who goes quiet after a reorganisation.

A new hire won't solve any of these, and neither will a wellbeing perk. They are design problems: how work is organised and how managers communicate.

What HR and leadership can do this quarter

1. Measure clarity, not just workload

Most pulse surveys ask whether workload is manageable. Few ask whether people know how their performance is judged. Add three statements to your next survey:

• I know exactly what is expected of me in my role.
• I know which decisions I can take on my own.
• When two priorities clash, I know who decides.

In Belgium, this fits inside the psychosocial risk analysis employers already have to carry out. Belgian law names five domains where these risks come from, and work organisation and work content are two of them.

2. Make a five-minute clarity check a manager habit

Sawhney's own advice is modest: regular check-ins between manager and employee. "It could be five minutes a month." Three questions are enough: what does success look like this month, what can you decide alone, and what can you drop?

3. Remove role conflict at the system level

One owner per priority. A clear tie-break rule when priorities collide. In matrix organisations, if someone reports to two people, those two people should agree on priorities before the employee has to referee between them.

4. Treat onboarding as role clarification

A meta-analysis of 70 newcomer samples found role clarity is one of the core markers of a successful start, and that a successful start predicts performance, satisfaction, commitment and retention. Onboarding that covers the tools but not the expectations is half an onboarding.

5. Watch the moments that create fog

Reorganisations, mergers, new leadership, AI rollouts. Each one rewrites roles. If nobody rewrites the expectations at the same time, you have created ambiguity at scale. Clarity also works hand in hand with psychological safety: people need to know what is expected, and to feel safe asking when they don't.

The fine print

Good evidence comes with limits, and these are worth knowing before you quote the numbers in a board meeting:

• Most studies in this field measure stress and outcomes at the same moment. That shows a strong, consistent link, not proof that fixing clarity will automatically raise performance.
• The percentages describe how the effect is split between the three stressors. They do not mean performance drops by 80%.
• The headline finding is in the paper's abstract. The outcome-by-outcome percentages come from the authors' own reporting.

Even with those caveats, the direction is consistent across six decades, and the fixes cost very little compared with a burnout or a resignation. If you want a sense of what long absences cost in Belgium, our piece on the 2025 work incapacity reform covers it.

Sources

• Sawhney, G., McCord, M. A., Cunningham, A., Cook, P., Adjei, K., & Flinn, T. (2026). A meta-analytic review of 60 years of role stressor research. Journal of Vocational Behavior, 167, 104234.
• Bauer, T. N., Bodner, T., Erdogan, B., Truxillo, D. M., & Tucker, J. S. (2007). Newcomer adjustment during organizational socialization: a meta-analytic review. Journal of Applied Psychology, 92(3), 707-721.

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