Worker voice is not an "add-on" tool. It's a Performance Driver.
- Nov 18, 2025
- 6 min read
Updated: Apr 15
A Labor Solutions Analysis | MIT Research, Nelson & Wilmers (2025)
Worker voice drives productivity. Not symbolically — measurably. New causal evidence from MIT shows that when manufacturers actively integrate worker input into production decisions, output rises by up to 15%, earnings increase, and turnover falls. For brands under CSDDD and human rights due diligence obligations, this is not a social outcome. It is a value chain capability.
Key Takeaways
Active worker voice is associated with productivity gains of up to 15% (Nelson & Wilmers, 2025, Table 3)
Wage and retention effects persist even after controlling for productivity — indicating a genuine shift in worker bargaining power, not just an output effect
Zero grievances at a supplier is not a safety signal. It is usually a sign the system is not trusted or accessible
CSDDD requires evidence of grievance mechanism effectiveness — not just existence. Worker-generated data is the only way to provide that evidence
The adidas WOVO programme — 402,500 workers, 47,200 grievances, 99% resolution, 79% satisfaction — is the published proof of what a functioning system produces at scale
Worker Voice Produces Measurable Business Outcomes — Not Just Compliance Data
Dylan Nelson and Nathan Wilmers at MIT have produced something rare in the labor space: causal evidence. Their study, Earnings Effects of Direct Worker Voice in Production (May 2025), examines what happens when manufacturers move from low to high use of worker input in production decisions. The findings are not subtle.
Moving from low to high use of worker input is associated with productivity gains of up to 15% (Table 3, pp. 19–20). Earnings increase. Turnover decreases. These are not correlation findings — the study uses quasi-experimental methodology to isolate the effect.
For brands, the downstream implication is direct. Factories that perform better produce more reliably: fewer last-minute production crises, more stable output, better absorption of demand volatility. When factories run more smoothly, downstream partners feel it.
This is what Labor Solutions has measured in the adidas WOVO programme for eight years. Worker satisfaction at adidas Tier 1 facilities rose from 39% in 2019 to 79% in 2025 — a 40-point gain built through consistent programme investment, not a one-time survey cycle.
The Distinction That Matters: Using Worker Input, Not Just Collecting It
Nelson & Wilmers make a finding that should change how every brand evaluates its worker voice programme. It is not the existence of a mechanism that drives performance gains — it is whether worker input is actively used in decisions.
Many programmes do the first. Very few do the second. Workers speak. Responses are logged. A PDF is produced at the end of a cycle. Nothing changes. A grievance mechanism that is not trusted, not used, and not acted upon is not a compliance asset — it is a liability, because CSDDD Article 9 requires evidence of effectiveness, not just existence.
Are workers' insights shaping decisions — or just filling reports?
The adidas WOVO programme demonstrates what an effective system looks like in practice. In 2025, 47,200 grievances were submitted by workers across 92 facilities — a 32% increase from 35,700 in 2024. The 99% resolution rate was maintained for the fourth consecutive year. Rising volume alongside a sustained resolution rate is not a problem. It is proof that workers trust the system enough to use it.
Zero Grievances Is Not a Safety Signal — It Is Usually a Sign of a Broken System
One of the most persistent misconceptions in human rights due diligence is that silence is good news. It is not. Zero grievances at a supplier almost always means one of three things: workers do not know the mechanism exists, they do not trust it, or they have learned from experience that speaking up carries risk.
The MIT study reinforces why this matters. The earnings and retention effects it documents persist even after controlling for productivity — meaning the benefit of worker voice is not simply that workers produce more and therefore earn more. It reflects a structural shift in how knowledge and influence are distributed at the facility level. Workers whose input shapes decisions become indispensable contributors. That indispensability shows up in wages and in retention.
A programme that workers do not trust cannot produce this effect. Which is why consistent usage, rising volume, and sustained resolution rates are not just a headline — they are evidence of a programme that workers have decided to rely on.
Frontline Workers See What Audits Cannot — and They See It First
Audits document the past. Workers report the present. Frontline workers are typically the first to notice deteriorating conditions, abusive supervision, wage inconsistencies, safety shortcuts, and the kind of operational friction that becomes a quality or compliance incident months later.
The WELL Worker Survey's electronics sector case study found that 35% of suppliers who passed their most recent social audit had workers paying illegal recruitment fees. Seventy-three percent of workers in the same cohort had low rights awareness — none of it visible to auditors. Audits check systems. Workers experience them.
When worker feedback is integrated into operational decisions — not logged and filed — those signals are captured early, interpreted in context, and acted on before they become non-compliances. That is real-time risk mitigation. It is also, as the MIT study shows, associated with measurably better facility performance.
Worker Voice Is a Value Chain Capability. Here Is What That Requires.
The Nelson & Wilmers study gives empirical backing to what practitioners in this field have observed for years: when worker voice is real, factories perform better and workers do better. For brands, that means worker voice belongs in sourcing strategy, risk management, HRDD and CSDDD reporting, and supplier selection criteria — not in a CSR workstream that sits beside the business.
If you are:
Building or assessing a worker survey programme — the WELL Worker Survey generates primary data directly from value chain workers, surfacing root causes that audits cannot see. Learn about WELL.
Looking for an operational grievance mechanism that workers actually use — WOVO CONNECT is an always-on, in-app mechanism that workers can access anonymously, with structured case management for suppliers and live dashboards for buyers. It is not a hotline. Learn about WOVO CONNECT.
Working to turn worker feedback into supplier-owned action plans — WOVO IMPROVE translates findings into structured, trackable improvement plans that suppliers own rather than manage. Learn about WOVO IMPROVE.
Ready to build the full programme — get in touch. We are happy to continue the conversation.
All findings from the MIT study cited in this post are drawn from Nelson, D. & Wilmers, N. (2025), "Earnings Effects of Direct Worker Voice in Production," ILR Review (May 2025). All adidas programme data is drawn from adidas' publicly available annual sustainability reports 2019–2025. Labor Solutions is the provider of the WOVO platform deployed across adidas' Tier 1 value chain.
Further Reading
Frequently Asked Questions
Does the MIT research apply to value chains specifically?
Nelson & Wilmers (2025) studied manufacturing facilities — the same operational context as most Tier 1 and Tier 2 value chain suppliers for fashion, electronics, and consumer goods brands. The productivity, earnings, and retention effects documented are directly relevant to the supplier facilities where brands have the most leverage and the most compliance exposure.
What is the difference between having a worker voice tool and actually using worker voice?
The MIT study is explicit: it is the active use of worker input in decisions — not the existence of a mechanism — that produces the performance effects. A survey that generates a report no one acts on does not qualify. An always-on grievance mechanism with consistent annual usage, 99% resolution, and rising year-on-year volume — like the adidas WOVO deployment — does.
How does this research connect to CSDDD compliance requirements?
CSDDD Article 9 requires companies to establish or participate in effective grievance mechanisms and demonstrate their effectiveness through usage data, resolution rates, and worker satisfaction — reported under ESRS S2. The MIT study provides independent academic evidence for why this matters operationally, not just legally: a functioning worker voice system produces measurable business performance, not just a compliance paper trail.
