A new class action lawsuit targeting smart ring maker Oura has reignited a broader debate about accuracy claims made by consumer health wearables powered by artificial intelligence.
The lawsuit, filed in California federal court, accuses Oura of overstating its ring’s sleep tracking accuracy by relying on AI-generated estimates rather than true clinical measurements.
The complaint was brought by Clarkson Law Firm on behalf of Madison Surber, a California resident who paid $513.68 for an Oura ring in 2025.
Surber’s complaint alleges Oura markets its rings as accurately identifying how much time users spend awake and in light, deep, and rapid eye movement sleep.
“But in reality, Oura rings cannot measure one’s sleep or cycles. That’s because sleep happens in the brain, not on one’s finger,” the plaintiff alleges in the filing.
According to Shireen Clarkson, co-founder of Clarkson Law Firm, Oura told consumers its rings could identify sleep stages with 95% accuracy relative to clinical sleep labs, while the true figure is nearer to 50%.
The complaint argues this gap is fundamental, as the ring’s sensors cannot capture the brain activity and eye movements that genuine clinical sleep staging requires.
The newest Oura ring uses a photoplethysmogram sensor, temperature sensors, and an accelerometer, none of which track brain activity, eye movement, cardiac electrical activity, or muscle activity.
Those omitted markers are precisely the ones typically monitored in clinical settings to build an accurate and medically meaningful picture of a person’s sleep.
The complaint states that Oura sold nearly 3 million rings in 2025, generating more than $1 billion in revenue, underscoring the commercial scale at stake in the legal dispute.
Oura published a peer-reviewed paper describing how its sleep-staging algorithm was developed and how it uses signals collected by the ring, according to a company spokesperson.
“Multiple third-party, independent studies support our claims of accuracy, and we have transparently reported on the mechanisms and measures that inform Oura’s sleep staging,” Oura’s spokesperson said.
“We’re committed to continuing to clearly communicate what Oura measures, what it estimates, and how members should use that information. We dispute the allegations and will defend against them in the appropriate legal forum,” the spokesperson added.
The case fits into a broader and growing tension between what health wearable companies promise consumers and what their devices can scientifically deliver.
Research has shown that heavy reliance on wearable readings can heighten stress and anxiety in some users, while others find the technology motivates healthier sleep habits and lifestyle choices.