# Measurement quality

Canonical HTML: /atlas/measurement-quality
Atlas version: atlas-2026-07-28-v1
Category: Quality, provenance, and observability

## Definition

Measurement quality is the degree to which telemetry supports the claim being made from it.

## How it works

Reliable observability separates online traffic, local tests, simulations, deterministic mocks, dashboard requests, resources, pages, and sessions.

## How to validate it

Require source class, environment, deployment, server and schema versions, resource type, status, latency, and a documented denominator.

## Common failure

Mixing synthetic crawler runs with public traffic produces precise-looking totals that answer no coherent question.

## Related topics

- [Source provenance](/atlas/provenance)
- [Crawler-facing error budgets](/atlas/error-budgets)