PBX SLAs are commitment indicators for call service speed and quality. For incoming calls: answer rate in X seconds, missed call rate, hold time. For outbound calls: appointment closing rate, on-time callback time. Setting the right KPIs helps you know whether your call center is "healthy" or "sick" and where adjustments need to be made. Zenify recorded an average response of 1.2 seconds and 98.4% AI accuracy.
TL;DR
- Switchboard SLA = commitment to speed + call quality.
- Incoming calls: answer time, missed call rate, hold time.
- Call out: rate of appointment closing and call back on time.
- Set realistic goals, measure hourly, adjust gradually.
- Good SLA is a management tool, not a "penalty point".
What is the switchboard SLA
SLA (Service Level Agreement) = quantitative indicators to measure call center quality:
Call to: customer calls → how long does it take for someone to answer, how many missed calls.
Call out: agent calls → appointment closing rate, script quality.
Purpose: know if the switchboard is running well, and where it needs to be fixed, not "an indicator to punish the agent".
KPI for incoming calls
KPI | Definition | Suggested goals
Speed to answer | Waiting time until someone is available | Under 1 minute normal time
Abandon rate | % of calls canceled before someone arrives | Under 5%
Response rate in X seconds | % of calls answered under X seconds | 80% under 30 seconds
Hold time trung bình | Thời gian chờ trung bình | Theo từng giờ
Note: Measured by the hour, peak hours are always different from off hours (see Hold time).
KPI cho cuộc gọi ra
KPI | Definition | Suggested goals
Appointment rate | % of calls reaching appointments/sending documents | Depending on the industry, 10-30%
On-time call back time | Did you call back on time as promised? 100% on time
Number of successful calls/hour | Calls to talk to guests | By team
Script quality | Achieve call target (QA dot) | Stable QM scores (see Quality monitoring)
Don't set a target of "maximum number of calls", the quality of the appointment is important, calling a lot without closing anything is a waste of time.
How to set actual SLA
1. Measure first, set goals later
Run 2-4 weeks to know the current number.
Goal = current + 10-20% improvement, not "drawing the sky" far from reality.
2. Place in groups, not in general
Peak hours are different from off hours; The sales team is different from the customer service team.
A single number SLA will be wrong in either time frame.
3. Measure daily, view weekly
Daily reporting: missed calls, hold time.
Look weekly/monthly to see trends, don't panic with a strange day.
4. Adjust as needed
Continuous failure → review human resources, routing, processes (see Workforce management).
Continuously going beyond → raising goals or reducing resources.
Errors when setting SLA
Set too high: fails → pressure on agent, "covering numbers", worse than no SLA.
There is only one indicator: looking at a number but forgetting quality.
Not measured by hour: "Average" SLA hides peak traffic jams.
Used for punishment: SLA becomes a "penalty point" → agent avoids, does not reflect the truth.