Diagnostic Integrity

Lab vs Field Data: The Crucial Distinction

Why synthetic tests and real user field data often tell different stories, and how PulseAudit strictly demarcates them.

What is Laboratory (Lab) Data?

Lab data is gathered under controlled conditions: a headless Chromium browser running on a fixed server, simulating a specific device (e.g. iPhone 14) and network profile.

Strength: Completely reproducible. Ideal for debugging regressions during pre-release staging sprints.
Limitation: Does not reflect real human browsing variability (diverse network bands, caching states, physical CPU thermal throttling).

What is Field Data (CrUX)?

Field data is collected continuously from real human users browsing your storefront in Google Chrome over a rolling 28-day window.

Strength: Represents actual shopper experience. This is the exact dataset Google uses for Core Web Vitals ranking signals.
Limitation: Aggregated over 28 days; slow to reflect recent code optimizations. Only available for domains with sufficient traffic.

PulseAudit's Strict Demarcation Rule

PulseAudit will never present lab measurements as real-user field data. When field data exists in Google CrUX, it is labeled FIELD / CrUX. If a domain has insufficient traffic, it is clearly marked NO FIELD DATA AVAILABLE.