thrive at work/Research/White paper
White paper · No. 01 · October 2026
The scientific foundations ofemployee capacity and engagement.
Capacity and engagement: what the evidence shows, how it was measured, and where it still has limits.
The thesis
Engagement tells an employer how people feel about the work. Capacity tells it whether they still have enough left to do it.
For three decades, employers have read the health of their workforce through engagement. Engagement describes the conditions at work. It does not show whether people have the energy, sleep, focus and resilience to work in them.
This paper tests the thrive at work framework, which measures both in one 55-statement assessment. Capacity scores were checked against heart, sleep, movement and cognitive measures in the same people over twelve months, and against outcomes across nearly 7,000 employees. The two measures share only a fifth of their variance, and capacity carries most of the link with days of not working effectively, deadline delivery and performance ratings.
Key findings
What the research shows.
- 01€19,800A year per employee: 71 more days unable to work effectively in the lowest capacity quarter than in the highest, valued at an average labor cost of €279 a day
Low capacity goes with about €19,800 a year in lost working time per employee
The quarter of employees with the least capacity reported about 85 days a year when they could not work effectively, against about 14 in the quarter with the most. That is a third of a working year. Ten points of capacity are worth about 19 working days a person a year.
- 0256%Share of priority tasks delivered on time in the lowest capacity quarter, against 86% in the highest
People with the least capacity deliver only about half their priority work on time
Ten points of capacity go with about 9 more percentage points of priority work delivered on time. Ten points of engagement go with 1.4.
- 031 in 5Average of 48.5 days a year an employee felt unable to work effectively because of exhaustion or stress: 22% of a 220-day working year
The average employee struggles to work effectively one working day in five
Workload, manager support and sleep each separate employees by about 50 of these days a year. Two of the three are in the employer's hands.
- 043×Days a year unable to work effectively: 59 in the Burning out group (high engagement, low capacity) against 18 in the Thriving group
Highly engaged but burning out: three times the days of not working effectively
An engagement survey reports both groups as healthy. Their engagement differs by under 4 points; their capacity differs by almost 20.
- 0576%Share of employees whose capacity score is below their engagement score; average gap 9.1 points on a 100-point scale
Three in four employees have less capacity than their engagement score suggests
Capacity sat below engagement in every one of the 90 demographic groups examined and in all 18 industries large enough to analyze.
- 0611 of 12Pre-set pairs of capacity scores and physical measures that showed a clear link; 100 employees in 20 organizations, measured three times over 12 months
Capacity scores move with the body
Capacity scores matched heart rate variability, resting heart rate, steps, measured sleep and cognitive tests. When a person's capacity rose over the year, their heart rate variability rose with it.
Methodology
How the research was done.
The framework draws on 196 peer-reviewed studies. In a 12-month study, 100 employees in 20 organizations completed the assessment three times alongside wearable, laboratory and cognitive measures. Three further data sets of nearly 7,000 employees tested how the assessment holds together and how it relates to outcomes.
The results are associations between groups, not causes. Days of not working effectively are self-reported. In normal use the assessment collects no device or biometric data.
Full methodology →What it means
What organizations can do.
Measure both, then act on the weaker one
Read capacity next to engagement, by team and group. Age and tenure alone separate people in the same workforce by 8 to 9 points of capacity.
Treat workload as a leadership measure
A sustainable workload is one of the clearest dividing lines in the data, and it is decided by the employer, not the employee.
Invest in managers
Manager support divides employees as sharply as workload does. Like workload, it is in the employer's hands.
Start with new joiners
People six to twelve months into a job have the least capacity of any tenure group. Onboarding that protects recovery reaches them when it counts.
The full paper
Inside the white paper.
- 01Part I · The framework: eight domains, two indices, one assessment
- 02Part II · Does the assessment measure what it claims?
- 03Part III · What the data show
- 04Part IV · How strong the evidence is, and where it is provisional
- 05Part V · 246 sources and the technical appendices
How to cite
thrive at work Research Division (2026). The Scientific Foundations of the thrive at work Framework: Methodology & Validation White Paper, first edition. https://www.thriveatwork.ai/research/scientific-foundations
Questions
About the paper.
Does the assessment collect biometric data?
No. The 12-month study used research devices and laboratory tests to check the assessment. In normal use, employees answer 55 statements and no device or biometric data is collected.
How is employee privacy protected?
Individual results stay with the employee. Employers see group results only: teams of five or more, and other groups of ten or more.
Who is the paper written for?
Scientific reviewers, partner researchers, and HR and business leaders who want to see how the measurement was built and tested before they rely on it.
What does the evidence not show yet?
The results are associations. Whether raising capacity changes outcomes, and how scores relate to an employer's own absence and turnover records, are the next studies.