Let’s consider a call center situation where hundreds of calls are handled every day. Management sees the overall numbers but doesn’t understand: why are customers complaining about long waiting times? Why are some calls not answered at all? Where exactly do the problems arise?

That is exactly why KPI monitoring exists — as a system that allows you to see the real picture and make well-grounded decisions.

What call monitoring really means

Monitoring is the regular tracking of a process over time, which answers three key questions:

What is happening now? Fixing the current state

How is the situation changing? Comparing different periods

What should be done next? Creating a basis for concrete management actions

If you focus only on speed or the number of calls, you may miss the main point: how stable and predictable the entire process is. And it is stability that is often the key to service quality.

Which metrics really matter

These metrics answer the question: how many customers actually received help — and how many did not?

What to track:

• how many calls were answered
• how many were lost due to lack of resources
• the ratio between handled and unhandled requests

For example, if you see that 20% of calls are lost due to unavailability, this is a clear signal of a shortage of operators or problems with workload distribution.

Speed KPIs: how quickly does the team respond?

Three aspects are important here:

Average response time: how long it takes from the incoming call to the start of the conversation with an operator. If this time keeps increasing, customers will wait longer — and their patience is not unlimited.

Waiting time to connection: the period when a person listens to music or an automated message. Every extra minute here increases the risk that the customer will hang up.

Call handling time: how long the conversation itself lasts. It’s important to understand: the goal is not to “get rid of” the customer as quickly as possible, but to resolve their issue effectively.

Stability KPIs: how manageable is the process?

This is the most interesting part and is often ignored. You may have decent average metrics, but if they “jump around,” it means the system is not under control.

What to look at:

• how much the metrics deviate from the average
• how often peak overloads occur
• whether results are consistent over time

If on Monday 95% of calls are handled, but on Friday only 60%, and this happens regularly, the problem lies in resource planning.

The key point: efficiency is not measured by a single metric, but by their combination.

How to build a working monitoring system

Step 1. Start with a clear goal

Not just “improve the metrics,” but specifically: reduce call losses by 15%, reduce average waiting time to 30 seconds, stabilize workload during peak hours.

Without a clear goal, you will collect data for the sake of data.

Step 2. Don’t take everything at once

For one goal, 2–3 metrics are enough. If you monitor ten KPIs at the same time, you will simply get confused and won’t be able to react in time.

For example, for the goal “reduce call losses,” it makes sense to track:

• Call answer rate
• Waiting time to connection
• Workload distribution among operators

Step 3. Fix the starting point

Without baseline values, you won’t be able to assess progress. If you are currently answering 75% of calls — this is your starting point. In a month, you will see: it became 80% — you’re doing well; it dropped to 70% — you need to investigate what went wrong.

Step 4. Define the analysis rhythm

Different tasks require different review frequencies:

Daily monitoring — for operational control. If the number of answered calls drops sharply today, you need to react immediately.

Weekly analysis — to identify trends. For example, maybe workload increases every Wednesday and work schedules should be adjusted.

Monthly review — for strategic decisions. Do you need to expand the team? Is the new call distribution system working?

Formulas: simple and clear

Answered Calls KPI

What it shows: what share of calls were successfully handled

Formula:

Answered Calls KPI (%) = (Number of answered calls / Total number of calls) × 100

Example:
Out of 1,000 calls, 850 were answered → your KPI is 85%

Lost Calls KPI

What it shows: how many customers were unable to reach you

Formula:

Lost Calls KPI (%) = (Number of unanswered calls / Total number of calls) × 100

Example:
150 lost out of 1,000 → that is 15% lost calls. Each such call is a potentially dissatisfied customer.

Process Stability KPI

What it shows: how predictable your system is

Formula:

Process Stability KPI (%) = (Number of periods within target / Total number of periods) × 100

Example:
Out of 20 working days, only 12 stayed within target → stability is 60%. This is a signal of systemic issues.

Important: formulas should be simple. If calculating a KPI requires complex math, you are adding complexity without real business value.

How to read the data correctly

The biggest mistake is to look only at the number and compare it to the target.
“Target 90%, actual 85% — bad.” But that’s just the surface.

What really matters:

1. Trend (how are the metrics changing?)

Not just “85% is bad,” but what was it before?

• Three months ago 90%, then 85%, now 80% → decline, action is needed
• It was 70%, then 80%, now 85% → progress, you are moving in the right direction

2. Recurrence (when do problems occur?)

Do metrics drop every Monday and Friday? That’s not random — it means you simply lack operators on those days. This is easy to fix by adjusting schedules.

3. Relationships (how does one metric affect another?)

Processing speed increased? Great! But check lost calls.
It may be that operators are handling complex requests superficially to save time, and those customers are forced to call again.

Key point: one metric tells you nothing. Look at several KPIs together and track changes over time — that’s when you see the real picture.

This systemic approach to performance analysis works equally well for all communication channels. If your team also handles text-based requests, it’s important to consider the specifics of chat support. For example, one agent can manage multiple chats at the same time, which changes the logic of workload calculation. For more details on how to properly measure FCR, response time, CSAT, and other chat-related metrics, see the material on KPI monitoring in chats.

Five common mistakes in call monitoring

1. Focusing on one KPI without balancing metrics

When all attention is on response speed, it’s easy to miss other critical aspects. Speed may look great, but if half of the calls are lost due to unavailability, the system is not working. Or vice versa: all calls are answered, but service quality suffers due to overload.

2. No acceptable target range

When there are no clear “normal” boundaries, it creates the illusion that higher is always better. But 100% answered calls achieved by 12-hour shifts with no breaks is not a success — it’s a direct path to team burnout and high turnover.

3. Ignoring seasonality

Comparing January to December may show a drop, even though this is natural dynamics. December typically has peak load due to holidays and sales. A correct comparison is December vs. last December — this gives a real view of performance trends.

4. Comparing data with different calculation logic

If last month you counted all calls 24/7, and this month only working hours, the metrics will automatically “improve.” But this is not real progress — it’s statistical distortion. The calculation methodology must remain consistent for valid period-to-period comparisons.

5. Reacting to single spikes instead of trends

One abnormally bad day due to a technical failure does not mean a systemic problem. Rebuilding all processes based on a one-time incident is an impulsive decision without analytical grounding. It’s important to log such cases, but evaluate the overall picture over a week or a month.

The role of data and analytics

Effective monitoring of the call handling process depends on the quality of the underlying data. Three key aspects determine the reliability of analytics:

Unified event logging rules

If one agent marks a call as “lost” after 10 seconds of waiting, while another does so after one minute, the statistics lose consistency. Different criteria for registering the same type of event make it difficult to compare results and analyze trends.

No duplicates

Each call should be counted only once. In practice, due to system configuration specifics, a single contact may appear in statistics multiple times: as an incoming call, as a transfer, and as a repeat contact. This distorts the real picture of workload and demand.

Stable calculation formulas

Frequent changes in calculation methodology make it harder to track real performance trends. An increase in a KPI may reflect not process improvement, but a formula change. If the calculation method must be updated, it is important to formally document this point to ensure correct period-to-period comparisons.

Frequently asked questions

Can call performance be evaluated using a single KPI?

One metric provides an oversimplified picture. For an accurate assessment, a combination of availability, speed, and stability KPIs is required. Otherwise, optimizing one parameter may negatively affect other parts of the process.

How often should call KPIs be monitored?

Operational metrics should be reviewed daily, but management conclusions are better based on weekly or monthly data. This helps avoid reacting to random fluctuations.

What is more important: absolute values or KPI trends?

Trends are more important. Even high KPI values do not guarantee stability if the metrics fluctuate significantly. Time-based analysis provides more insight than isolated numbers.

How should seasonality be taken into account in call KPIs?

Seasonality should be tracked separately, and metrics should be compared with equivalent periods. Without this, KPI increases or decreases may be misinterpreted as problems.

Should KPIs be reviewed over time?

Yes. Changes in processes or workload require KPI updates. It is important to document any changes to preserve valid historical comparisons.

Can KPIs be the same for different companies?

The methodology may be shared, but specific KPIs and their threshold values always depend on the company’s process structure and business goals.

Key takeaway

KPI-based call monitoring is about making the voice channel manageable and predictable.

When you consciously select metrics, track them regularly, and analyze them over time, KPIs turn from formal reporting into a tool for forecasting and optimization.

Start small: choose one specific goal, 2–3 metrics to track it, fix baseline values, and within a month you will see how much better you understand your processes.