Affiliate & AI Disclosure

Transparency matters. Here is exactly how CircaTest is built, how it earns revenue, and how (and why) those things do not influence the content.

AI Content Disclosure

CircaTest is built entirely with AI. All content on this site — reviews, comparisons, guides, summaries, product cards — is generated by artificial intelligence. No content represents first-person testing, hands-on use, or in-house laboratory measurement.

AI-generated content is sourced exclusively from publicly available data:

• Peer-reviewed validation studies indexed in PubMed and major academic databases
• Manufacturer-published specifications and product pages
• FDA 510(k) regulatory filings and other public regulatory documents
• Aggregated user reports from public communities and reviews

Where data is unavailable for a specific device or model (for example, the Samsung Galaxy Ring has no published PSG validation data at the time of writing), the article states this explicitly. We do not fabricate accuracy numbers, citations, or regulatory clearance numbers.

Errors are possible in AI-generated content. If you find one, please email hello@circatest.com and we will correct it.

How CircaTest Earns Revenue

CircaTest earns money through affiliate commissions and advertising. When you click an affiliate link on this site and make a purchase, CircaTest may earn a small commission at no additional cost to you.

Affiliate Programs

• Amazon Associates: CircaTest is a participant in the Amazon Associates program. We earn commissions on qualifying purchases made through links to amazon.com. Our Amazon Associates tag is circatest-20.

Editorial Independence

Editorial content is never influenced by affiliate relationships. Rankings, accuracy figures, and recommendations are determined by published research, manufacturer specifications, FDA filings, and aggregated user reports — not commission rates. If a device performs poorly in published validation studies, the article reflects that, regardless of whether the device generates more affiliate revenue than its competitors.

Concretely: the Withings ScanWatch 2 currently ranks lowest in Cohen's kappa among the six devices in Schyvens et al. (2025)Cited studyA performance validation of six commercial wrist-worn wearable sleep-tracking devices for sleep stage scoring compared to polysomnographySchyvens AM et al. · Sleep Advances · 2025Single most editorially important study in the CircaTest corpus. Six commercial wearables tested against PSG in a uniform protocol means the kappa values are directly comparable in a way most validation studies are not. Drives the head-to-head accuracy figures across CircaTest's comparison content. Limitations: tested previous-generation models (Series 8 not 10, Charge 5 not 6, original ScanWatch not 2) so the results are upper bounds for current models, not direct evidence.View full record →. That fact is reported plainly even though the ScanWatch 2 is one of our affiliate-linked products.

Not Medical Advice

CircaTest covers consumer sleep trackers, including some with FDA clearances. Nothing on this site is medical advice. FDA clearance for a consumer wearable is for screening, not diagnosis. If you have concerns about your sleep or breathing, consult a qualified healthcare provider.

FTC Compliance

In accordance with Federal Trade Commission (FTC) guidelines, we disclose that this site contains affiliate links and that all content is AI-generated. This disclosure applies to every page on circatest.com.