Deterministic Matching

The Short Answer

Deterministic matching links records using exact, known identifiers, such as an email address, phone number, or login cookie. If the same email appears in two datasets, deterministic matching treats them as the same person with high confidence. It is the most accurate matching method available, but it only works when a shared identifier actually exists between the two records being compared.

How It Works

Two records are compared on a shared, exact identifier, most often a hashed email address or phone number. If the identifier matches exactly, the records are merged with high confidence. No inference or scoring is involved: it is a direct, rules-based comparison.

Why It Matters

Deterministic matching is the gold standard for accuracy because it does not guess. Platforms lean on it first, then fall back to probabilistic matching only when no shared identifier exists between the records being compared.