Don't Kill Telephony: Why ASR and ACD Scores Matter

If you run outbound calling at any scale, two numbers tell you almost everything about the quality of your traffic: ASR and ACD. They are simple to calculate, but they carry real weight. Carriers watch them, regulators care about what they imply, and the long-term viability of telephony as a channel depends on keeping them healthy. Here is what each metric means, what counts as a good score, and what to do when yours slips.

How do you calculate ASR and ACD?

ASR (Answer-Seizure Ratio) is the percentage of attempted calls that connect successfully:

ASR % = (answered calls / total calls attempted) × 100

ACD (Average Call Duration) is the average length of the calls that do connect:

ACD = total duration of answered calls / number of answered calls

Some carriers call ACD “ALOC” (Average Length of Call) — same idea. Both are used to judge network quality, which is exactly why call centers need to track them and keep them in a sensible range.

What counts as a “good” ASR and ACD?

Scores that are too low signal poor-quality traffic flowing across the network. As a rough guide:

Metric	Excellent	Acceptable	Problematic
ASR	60% or above	40%–50%	Below 40%
ACD	Over 6 minutes	3–4 minutes	Under 1 minute

An ACD under a minute is a red flag worth investigating immediately.

Do these numbers vary by country or industry?

Yes. Geography matters, mostly because network quality differs from one region to the next. Industry and brand matter just as much. If you sell a complex product, or one with strong brand recognition, your ACD tends to run higher because people stay on the line. Other calls are simply less welcome: in France, tax-optimization offers and door-to-door-style phone or internet subscription pitches often see very low ACD, and pickup rates that barely register.

What does a low ASR or ACD mean?

In a call-center context, several distinct factors can drag these numbers down.

Low ASR

Recipient behavior. A low ASR often means large volumes of calls — frequently driven by dialers — are going out with nobody answering. The usual causes: contact lists are out of date (dead numbers), recipients recognize the traffic as unwanted and let it ring, or they simply aren’t available (calling landlines during working hours). People who feel hounded by unsolicited calls also tend to take it out on the operator carrying the traffic.

Predictive dialer set too aggressive. It is tempting to push dialers to maximum volume for a short-term productivity spike, but that backfires. Dial too slowly and agents sit idle. Dial too aggressively and a flood of calls gets cancelled because every agent is already busy — which tanks your ASR and eventually runs you into carrier limits. Aggressive predictive dialing is one of the most common reasons call centers see low ASR. Find the rhythm that balances idle agents against cancelled calls.

Busy lines. A call that reaches a busy destination counts as a failed call.

Far-end switch congestion. This tells you a center is placing too many calls to the same small area — one building, one small town — for the local switch to handle.

Low ACD

A low ACD (under three minutes) often means the person you reached doesn’t see value in the conversation. But technical problems are just as likely to be at fault.

Audio quality. Distant-sounding voices, echo, dropouts (from low-quality codecs, jitter, or packet loss), and stretches of dead air all push recipients to hang up fast. NAT and network-configuration problems frequently cause one-way audio, which also ends calls. And watch your bandwidth: every connection has a ceiling on the number of concurrent agents it can carry at good quality. Push past it and audio degrades for everyone.

Looping. Repeatedly redialing the same wrong number drags your scores down for no return.

Why do these metrics matter?

Carriers dislike low ASR and ACD because the scores reflect badly on their network. Calls that go unanswered or end in seconds generate little revenue while still consuming resources, which creates friction between the carrier and the call center. Carriers can respond by blocking the worst offenders, raising prices, or shunting low-quality traffic onto dedicated channels. Keeping your scores reasonable keeps that relationship workable.

Zoom out and the stakes are bigger. Marketing, polling, and outbound sales by phone only work as long as people actually pick up and listen. If call quality slides or people feel spammed, they sign up for do-not-call lists, complain to regulators, ignore unknown numbers, and let everything go to voicemail. Keeping the telephone experience reasonably pleasant is what keeps it a viable channel at all — degrade it far enough and you kill its value as a marketing, sales, or survey tool entirely.

How do you fix a low ASR or ACD?

1. Clean your data, before and after. Before a campaign, run an HLR (Home Location Register) lookup to flag invalid mobile numbers before you ever dial them. After a campaign, prune your database by checking your CDRs (Call Detail Records) and removing numbers that never connected.

2. Tune your predictive dialer to the productivity sweet spot. Aim for the balance where an agent is almost always on a live call but prospects rarely answer to dead air. Your dialer vendor can help you calibrate this.

3. Target better. Call at times that suit your audience, and segment your list down to people genuinely likely to care about your offer. Campaigns that bother too many people will see ASR and ACD fall accordingly.