Evidence base
From research to practice: how evidence shapes what we do.
For each body of evidence we show you what the research says, what it means for you as an employer, and what we actually do about it.
1 · Research finding
Harvard Human Flourishing Program
Flourishing is broader than mental health.
Tyler VanderWeele's 2017 framework describes five core domains: happiness and life satisfaction, mental and physical health, meaning and purpose, character and virtue, and close social relationships. The extended Secure Flourish measure adds financial and material stability.
VanderWeele, On the promotion of human flourishing, PNAS (2017).
Scope and limitations: A conceptual and measurement framework, not a study validating WWS. Our six workplace pillars are a distinct evidence-informed framework, not the Harvard measure.
2 · What this means for employers
Wellbeing is broader than mental health. A strategy that only covers stress or only covers benefits misses most of what makes people flourish.
3 · What WWS does
We assess all six pillars, from purpose and relationships to financial wellbeing, so investment goes where the gap actually is.
1 · Research finding
Gallup
Employee engagement is associated with business outcomes.
Gallup's 2024 Q12 meta-analysis found associations between business-unit employee engagement and outcomes including productivity, turnover and safety. It brings together studies across organisations rather than measuring the effect of one wellbeing programme.
Gallup, The relationship between engagement at work and organisational outcomes: Q12 meta-analysis, 11th edition (2024).
Scope and limitations: Business-unit research with observational and predictive analyses. Association does not establish that engagement alone causes the differences, or predict a WWS client's results.
2 · What this means for employers
Day-to-day management deserves attention alongside central programmes. Workload, support and team relationships are practical places to start.
3 · What WWS does
We build manager capability in workload conversations and early support, and track results at team level, not just across the organisation.
1 · Research finding
World Health Organization (WHO)
Mental health at work is a system-level responsibility.
The WHO's 2022 guidelines recommend organisational interventions addressing psychosocial risks, alongside manager and worker training, individual support and return-to-work measures.
WHO, Guidelines on mental health at work (2022).
Scope and limitations: Evidence-based guidance, not a single employer study or a guaranteed effect size. The strength and certainty of evidence differ across recommendations.
2 · What this means for employers
Do not rely on resilience training alone. If workload, leadership and job design keep producing strain, individual support only absorbs it.
3 · What WWS does
We diagnose workload, leadership and psychosocial risk before choosing any intervention, and change working conditions before adding services.
1 · Research finding
Prof. Amy Edmondson (Harvard Business School)
Psychological safety is associated with team learning.
Edmondson's 1999 field study of 51 work teams in one manufacturing company found that psychological safety was associated with learning behaviour, which was associated with team performance. Google's internal Project Aristotle studied 180 teams and identified psychological safety among five dynamics of effective teams.
Edmondson, Psychological Safety and Learning Behavior in Work Teams, Administrative Science Quarterly 44(2), 350–383 (1999); Google Project Aristotle, public findings (2015/2016).
Scope and limitations: Edmondson's field study does not establish a universal ranking of predictors. Google's internal analysis was specific to its organisation and was not an independently peer-reviewed study. Neither supports calling psychological safety the strongest single predictor across workplaces.
2 · What this means for employers
When speaking up feels risky, concerns may go unreported. Read surveys alongside conversations and other evidence rather than treating one score as decisive.
3 · What WWS does
We assess psychological safety at team level using research-informed measures and conversations, then help leaders practise supportive behaviours. Adapted questions should not be presented as a validated scale.
1 · Research finding
Deloitte
Mental health interventions can offer financial returns, but results vary.
Deloitte's 2024 review of 26 literature sources reported an average return of around £4.70 for each £1 invested in workplace mental health interventions. The often-quoted £5 per £1 figure comes from its earlier 2020 report, not the 2024 review.
Deloitte, Mental health and employers: the case for employers to invest in supporting working parents and a mentally healthy workplace (2024); refreshing the case for investment (2020).
Scope and limitations: A review of reported financial returns from varied interventions, not a single controlled trial. The 26 literature sources are separate from the UK employee survey used for Deloitte's employer-cost estimates. An average is not a forecast for your organisation or a WWS client result.
2 · What this means for employers
Use this evidence to make the case for evaluating mental health investment, not to promise a fixed return or rank every type of intervention. Choose support around the needs you find.
3 · What WWS does
We put budget into diagnosis, prevention and manager capability, and agree outcome measures up front so return can be tracked.
1 · Research finding
McKinsey Health Institute
Holistic health is associated with employee experience and performance.
McKinsey Health Institute's 2023 survey of more than 30,000 employees across 30 countries examined mental, physical, social and spiritual health. Better self-reported holistic health was associated with more positive workplace outcomes, including self-reported job performance.
McKinsey Health Institute, Reframing employee health: moving beyond burnout to holistic health (2023).
Scope and limitations: A cross-sectional employee survey, not an experiment. Self-reported associations do not establish that a particular intervention causes better performance.
2 · What this means for employers
Look beyond a single health score. Consider working conditions and individual support together, and check what changes in your own organisation.
3 · What WWS does
We treat wellbeing as part of how the organisation runs, with indicators reviewed alongside operational performance.
We also draw on ISO 45003, German DIN guidance, the Job Demands–Resources model (Bakker & Demerouti), Self-Determination Theory (Deci & Ryan), and positive organisational scholarship (Dutton, Cameron). Every recommendation we make can be traced back to a specific evidence base.