When outbound performance drops, three letters often show up in the carrier conversation: ASR, ACD, and PDD.
They are useful metrics, but only if the manager understands what each one can and cannot prove.
A low ASR does not automatically mean the carrier is bad. A high ACD does not automatically mean the route is excellent. And long PDD can make agents think the dialer is slow even when the real delay happens downstream.
What is ASR?
ASR stands for Answer Seizure Ratio.
It compares answered calls with total call attempts or seizures under the reporting definition being used.
In simple form:
ASR = Answered Calls / Total Call Attempts x 100
If 1,000 attempts produce 180 answered calls, the ASR is 18%.
Does low ASR mean the carrier route is bad?
Not by itself.
ASR is affected by user behavior as well as network performance.
A list full of unanswered consumers can produce low ASR even when the route is technically healthy. Busy numbers, no answers, rejects, caller ID reputation, time of day, and lead quality can all change the result.
That is why ASR is useful as a trend and comparison metric, not a standalone verdict.
What is ACD in VoIP?
In carrier reporting, ACD commonly means Average Call Duration.
It measures the average length of answered calls under the provider’s calculation.
A route that connects many calls that immediately fail may show a much lower ACD than a route carrying genuine conversations.
Does high ACD always mean a good route?
No.
Campaign type matters.
A verification campaign may have naturally short calls. A sales campaign may have longer calls. Voicemail detection, transfers, and answering machines can also affect duration.
Compare similar traffic rather than using one universal ACD target.
What is PDD?
PDD stands for Post-Dial Delay.
It is the time between starting the call and receiving the progress indication that the destination is ringing or otherwise progressing, depending on the measurement definition.
Long PDD makes calls feel slow to set up.
Why does high PDD matter to a dialer?
If every call takes several extra seconds before ringing, the dialer holds call resources longer before it knows the outcome.
That can affect pacing, agent wait time, abandonment behavior, and the number of simultaneous attempts needed.
What can cause high PDD?
Possible causes include:
- Long carrier routing chains
- Slow downstream networks
- Congestion
- Route hunting
- International interconnects
- Signaling delays
Look for whether PDD changes by carrier, destination, or time of day.
How should ASR and ACD be read together?
The combination is more useful than either number alone.
Examples:
- Low ASR, normal ACD – few calls answer, but answered calls behave normally
- Normal ASR, very low ACD – calls connect, but many end quickly
- Low ASR, low ACD – could indicate poor traffic quality, route issues, caller ID problems, or a weak lead set
Those are investigation signals, not automatic diagnoses.
What other metrics should be checked with ASR, ACD and PDD?
Useful context includes:
- SIP response-code distribution
- Busy and no-answer rates
- Answering-machine rate
- Carrier or route
- Destination prefix
- Caller ID
- Time of day
- Call concurrency
- CPS
Why can two carriers show different ASR on the same leads?
Routing, caller ID handling, filtering, downstream networks, and timing can differ.
But the comparison needs to be fair.
If Carrier A receives Florida leads during prime hours and Carrier B receives a different state later in the day, the ASR comparison tells you very little about route quality.
How do you test two VoIP routes properly?
Use comparable traffic.
Split similar lead inventory, run it during similar time windows, use comparable caller ID strategy, and collect enough attempts to reduce noise.
Then compare:
- ASR
- ACD
- PDD
- SIP failures
- Cost
- Audio quality
Can dialer settings affect these metrics?
Yes.
Dial timeout, AMD, lead selection, pacing, time-zone rules, and caller ID strategy can all change the traffic a carrier sees.
Do not blame the route before checking whether the campaign itself changed.
What should a route-quality dashboard show?
A useful manager view breaks metrics down by:
- Carrier
- Route
- Campaign
- Destination
- Hour
- Caller ID pool
One monthly average hides too much.
For teams that want route metrics connected to campaign reporting, Consaltek’s custom reporting and operations services can support that data layer.
What mistakes lead to bad route decisions?
Judging a carrier from ASR alone
Lead quality and customer behavior influence ASR.
Comparing different traffic sets
A carrier test is only useful when the underlying traffic is comparable.
Ignoring PDD
A route can answer calls but still feel painfully slow to set up.
Looking only at monthly averages
Destination or hourly failures can disappear inside the average.
Frequently Asked Questions
1. What does ASR mean in VoIP?
ASR means Answer Seizure Ratio, the proportion of call attempts that result in answered calls under the reporting definition.
2. How is ASR calculated?
A common calculation is answered calls divided by total call attempts, multiplied by 100.
3. Is higher ASR always better?
Higher ASR can be positive, but it is influenced by lead behavior, destination, time, caller ID, and route quality.
4. What does ACD mean in carrier reports?
ACD usually means Average Call Duration for answered calls.
5. Is ACD the same as Automatic Call Distribution?
The acronym can mean different things in different contexts. In carrier route statistics, ACD usually refers to Average Call Duration.
6. What is PDD?
PDD means Post-Dial Delay, the delay between starting a call and receiving ringing or another call-progress indication under the provider’s measurement.
7. What causes low ASR?
No answers, busy numbers, poor lead quality, caller ID reputation, route failures, filtering, and campaign timing can all contribute.
8. What causes low ACD?
Short campaign calls, answering machines, early disconnects, poor audio, false answers, or other traffic behavior can reduce ACD.
9. What causes high PDD?
Long route chains, downstream signaling delays, congestion, route hunting, and network conditions can increase PDD.
10. Can low ASR be a dialer problem?
Campaign settings can affect the traffic, but ASR alone cannot identify the cause.
11. Can caller ID reputation affect ASR?
Yes. If recipients or networks treat the number as suspicious, answer behavior can change.
12. Should I compare carriers using the same lead file?
Use comparable lead segments, time windows, caller ID strategy, and campaign settings for a meaningful test.
13. What is a good ASR?
There is no universal benchmark. Compare against similar traffic, destinations, and historical performance.
14. What is a good ACD?
It depends heavily on campaign type. Compare similar call flows rather than applying one target to every operation.
15. Which metric should I watch first when a route feels bad?
Look at ASR, ACD, PDD, SIP responses, audio quality, and destination patterns together rather than choosing one number.
Final Takeaway
ASR tells you how often attempts become answered calls. ACD tells you how long answered calls last. PDD tells you how long call setup takes.
None of them can diagnose a route alone.
Use them together, compare equivalent traffic, and break the data down by carrier, destination, caller ID, and time. That is how a dialer manager separates a real route problem from weak lead data or campaign behavior.