Answer seizure ratio meaning

In telecoms contracts, regulatory work and disputes, the answer seizure ratio (ASR) describes call-completion quality: the percentage of outbound call attempts that, having seized capacity and left the originating exchange/switch, return an answer signal. In practice, it is answered seizures divided by total seizures, expressed as a percentage. The “answer signal” is the network indication that a call has been answered (for example, ISUP Answer Message or SIP 200 OK). ASR is not defined in UK or Irish legislation or case law; it is an industry metric referenced in Ofcom and ComReg contexts and informed by international standards (such as ITU‑T recommendations). It is widely used in interconnection and wholesale voice termination agreements (as a KPI for service levels and service credits), in routing and quality of service disputes, in allegations of traffic pumping or call blocking, and as evidential data in litigation and regulatory investigations. Methodology can vary. Contracts should specify the data source (CDRs/signalling logs), measurement window and geography, and which events count as seizures or exclusions (for example, network failures, user busy, no‑answer, early media, or spam blocking). Usage is broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland.