What do ASR and ACD stand for and why are those values important?

What is Average Call Duration (ACD)?

The average call duration (ACD), sometimes also called ALOC = Average Length of Call, is a measurement in telecommunications that reflects the average length of telephone calls transmitted on telecommunication networks.

The measurement is typically based on the reporting by telecommunication equipment via call detail records. Samples are collected to determine traffic demand and forecast call volumes, serving also as a tool for infrastructure monitoring of switches and cables. Depending on the type of call being made, ACD can be used as a proxy measure of call quality.

The most used formula is: ACD = duration of all answered calls/number of answered calls 

What is Answer-seizure ratio (ASR)

In telecommunication, an attempted call is termed a seizure.
The answer-seizure ratio is defined as 100 times the ratio of answered calls, i.e. the number of seizures resulting in an answer signal, to the total number of seizures:

The most used formula is: ASR % = (total number of answered calls / total number of calls) × 100

Busy signals and other call rejections by the telephone network count as call failures. However, the inclusion in the ASR accounting of some failed calls varies in practical applications. This makes the ASR highly dependent on end-user action. Low answer-seizure ratios may be caused by far-end switch congestion, not answering by called parties and busy destination circuits.

Why are good ASR and ACD values so important?

ASR and ACD scores that are too low indicate poor quality of traffic passing through networks’ infrastructures.
As we use Premium Plus quality for all our solutions. This quality does not allow for poor quality traffic or dialer/automated/short-burst traffic at all. Our quality solutions are created for high-quality human to human phone calls and are priced as low as we can. Short-burst traffic could influence the quality and reliability of any service to other clients. To prevent any such risks we have never allowed this type of traffic on our standard solutions and networks.
The system will track for this and shut down any account that does not abide by the rules. If this happens we will contact you to discuss and work towards a possible solution. Until such is agreed and implemented, your accounts will remain blocked.

An exceptionally good ASR score would be 60% or above.
40% – 50% is considered acceptable. Anything below 40% is considered quite poor.

For ACD, calls lasting longer than 6 minutes are excellent, while anything at the 3 or 4-minute mark is considered acceptable.
Any serious volume of calls below 1 minute should be considered very problematic.

Does this vary according to country or industry?

Yes, ASR or ACD scores can vary by geographic location, principally due to the quality of the network in that area and we are fully aware of this. That is why we exclude and/or limit certain industries for example, as a safeguard.

Industry and brand matter as well: if you’re selling a complex product or one with good brand recognition, ACD can be relatively high. However, certain calls are perceived as less desirable than others: for tax optimization calls (frequent in France), as well as sales calls for phone or internet subscriptions, ACD can dip quite low, and pick up rates might even be non-existent.


Partly sourced from Wikipedia on ACD and Wikipedia on ASR

Last updated: 01/01/2024



© Voyced
All information provided is copyrighted and purely informative in nature. It is maintained by Voyced with the greatest of care using reliable sources only.
Given the fast evolution of the telecom sector, Voyced does not offer any guarantee about the accuracy and completeness of the information offered. 
We explicitly do not give anyone permission to use this information in any other way than to inform themselves about what (legal) requirements there may be and they need to comply with when registering Services and/or DIDs with Voyced.

  • ASR, ACD, Short-burst, Premium Plus Traffic, Average Call Duration, Answer-seizure ratio
  • 3 Users Found This Useful
Was this answer helpful?

Related Articles

What is a TopUp?

A TopUp is the process of adding call credit to your account so that you can make calls.You can...

What is (TopUp) Call credit

As Voyced is a prepay system, you'll need to have credit to make a call.Once you get near to the...

How do I TopUp / add call credit?

You can buy a TopUp online, in our Client area, and an invoice for that TopUp will automatically...

My call credit is running out what should I do?

Once you get near to the end of your credit, you will be notified when you make your next call...

What do I get and what do I need to sign up with Voyced?

Connected to the world If you “just” need a SIP / VoIP account with a real telephone number for...