AI inference glossary

Benchmark metrics

Draft acceptance rate

Also known as acceptance rate, speculative acceptance rate, draft acceptance ratio

In plain English

Draft acceptance rate is the fraction of proposed tokens that pass verification, rather than the number emitted by each verification step.

Technical definition

Draft acceptance rate is the number of accepted draft tokens divided by the number of proposed draft tokens over a specified sample.

Relationship

draft acceptance rate = accepted draft tokens / proposed draft tokens

Engineering details

It is a dimensionless fraction, often reported as a percentage. Acceptance length instead counts tokens per verification step. With a fixed draft length and matching counting rules, the accepted-draft length equals draft length times acceptance rate. An engine may include a target-generated bonus token in its reported length, so that convention must be stated separately.

Why it matters

The same acceptance rate can correspond to different numbers of accepted tokens when draft lengths differ. Neither rate nor length alone determines speedup: draft generation, verification cost, batching, and rejected work also matter.

How to read it in InferenceX

AgentX uses externally calibrated acceptance behavior for synthetic replay. Compare the draft length, speculator, counting convention, and forced-versus-natural setting before treating two reported acceptance values as equivalent.

See the concept in real benchmarks

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