A major international study has found that uncertainty about job responsibilities and expectations may be the most damaging source of workplace stress, even more than excessive workloads or long working hours.

The findings, published in the Journal of Vocational Behavior, are based on a sweeping meta-analysis examining six decades of workplace psychology research.

Study analysed data from 80,000 workers

Researchers reviewed hundreds of academic studies published between 1964 and 2024, analysing responses from nearly 80,000 participants across 515 independent studies and 558 research samples.

The study focused on three major workplace stressors:

  • Role ambiguity
  • Role conflict
  • Role overload

Among them, role ambiguity emerged as the most harmful.

Unclear expectations quietly damage wellbeing

Researchers described role ambiguity as the uncertainty employees experience regarding responsibilities, expectations, priorities, and performance standards.

According to the study, employees who lacked clarity about their roles were more likely to experience:

  • Reduced confidence
  • Lower motivation
  • Declining engagement
  • Poorer performance perception

The study also found that uncertainty often discourages employees from taking initiative or going beyond their formal job duties.

Over time, workers reportedly begin second-guessing priorities and feel increasingly unsure about how their success is being measured within organisations.

Burnout and health problems linked to other stressors

While role ambiguity had the broadest negative impact, researchers found that role conflict was the strongest contributor to burnout, emotional distress, and intentions to quit jobs.

Work overload, meanwhile, showed the strongest connection to deteriorating physical and mental health.

The findings suggest that modern workplace stress is not caused only by heavy workloads, but also by fragmented communication and unclear organisational structures.

Researchers say theory remains relevant today

The study revisited the long-standing “role stressor theory”, first introduced in workplace psychology during the 1960s.

Despite changes in work culture, technology, and hybrid working environments, researchers said the theory remains highly relevant today.

Experts believe the findings could help organisations reduce burnout and improve employee wellbeing by prioritising clearer communication, defined responsibilities, and transparent expectations