Citation share

The metric is measured two ways. Third-party tools sample queries at scale and count who the engines cite — the approach behind the published rankings of most-cited domains. And the engines themselves have begun shipping first-party numbers, which replaces estimation with measurement wherever it is available.

Its caveats are structural. Citation share is engine-specific: the same content earns different shares in different engines. It is model-sensitive: results shift when the engine swaps the model underneath. And methodology varies by measurer — query sets, geographies, and counting rules differ, so numbers from different sources rarely reconcile cleanly.