Measuring Call Success: Why ‘Answered’ Is the Wrong KPI

So, you miss a customer call every once in a while. No big deal, right? Up to 60% of calls go unanswered anyway, meaning it’s a common occurrence.

Unfortunately, missed calls not only frustrate customers but also result in revenue leakage. You might assume the customer will leave a voicemail or call back later. However, 85% of people whose calls are not answered will not call back, and 85% of unanswered calls go unreturned.

Even if you make a concerted effort to decrease the number of missed calls at your business, it’s important to note that answering isn’t the same as resolving. You might have already noticed signs missed or unresolved calls are impacting your business. Maybe it’s declining sales metrics, stagnant revenue, or poor reviews from customers. Perhaps your sales team is finding it harder to close deals.

Whatever the consequences, understanding why measuring call success beyond only “answered” is essential to addressing them and guiding you in the right direction. The first step is understanding how revenue leakage affects your business beyond just your bottom line.

The Results of Revenue Leakage

Revenue leakage occurs when a business fails to capture, record, or collect revenue it has already earned or had a clear opportunity to earn and is more common than many businesses realize. An estimated 42% of companies experience some form of revenue leakage, with businesses losing between one to five percent of Earnings Before Interest, Taxes, and Amortization (EBITA) annually.

Larger enterprise organizations lose an average of 20% of revenue to leakage. Unlike one-time monetary losses, revenue leakage is recurring and structural, repeating day after day without clear visibility or accountability. After-hours missed calls are especially costly because they’re some of the most valuable opportunities to interact with your customers.

How Missed Calls Create Revenue Leakage

Missed calls are a direct and measurable source of revenue leakage that often goes unnoticed. Every unanswered call represents a customer who was ready to buy, book, or request service. Studies show that 78% of callers will do business with the first company they successfully reach, meaning the cost of a missed call is often revenue lost to a competitor.

Even when you attempt to recover missed opportunities through callbacks, the results are weaker. Conversion rates markedly drop when the first interaction isn’t answered live, and your staff time is diverted toward follow-ups, voicemail checks, and repeated explanations. This quietly increases labor costs and reduces productivity.

Agent performance plays a critical role in handling missed calls and follow-ups, as effective agents can help recover lost opportunities and improve customer satisfaction. Effective agent performance is crucial to resolve customer issues promptly and prevent further revenue loss, especially when missed calls disrupt the customer journey.

Revenue leakage can be mitigated by implementing revenue assurance strategies, such as automated billing systems and data analytics, which help companies identify and address gaps before they become costly problems. A company that doesn’t master revenue collection will eventually not be able to do some of the things it wants to do.

The Hidden Math Behind Missed Calls

The financial impact of missed calls adds up faster than many businesses expect. This formula illustrates the risk by calculating the average number of missed calls and their potential cost:

Missed calls per month × Average call value × 12 months × 85% (callers who won’t try again)

Call rate and call tracking can be used to monitor missed calls over time, helping businesses identify trends and address underlying issues that lead to lost opportunities.

For example, a business missing 50 calls per month with an average value of $500 per call could be losing:

50 × $500 × 12 × 0.85 = $255,000 in annual lost revenue

Tracking handled calls alongside missed calls is essential for understanding the full impact on agent productivity and overall call center performance.

That figure only accounts for immediate sales. It doesn’t capture the long-term effects of decreased customer trust, lost repeat business, or missed referrals.

Call Arrival Rate and Call Volume

Call arrival rate and call volume are foundational metrics in call center operations, serving as the pulse of your customer engagement and a key driver of revenue generation. The call arrival rate tracks how many incoming calls your center receives within a set timeframe, while call volume reflects the total number of calls handled by your team. Together, these metrics offer immediate visibility into customer demand and the effectiveness of your response.

Monitoring call arrival rate and call volume is essential to identify revenue leakage and prevent revenue leaks before they impact your bottom line. When there’s a gap between the number of customer calls received and those properly billed or resolved, revenue slips through the cracks. This often happens due to faulty processes, manual invoicing, or billing errors, especially in poorly organized companies or those relying on outdated manual processes. By regularly analyzing sales data, reviewing call recordings, and auditing your billing system, you can calculate revenue leakage and pinpoint where revenue loss is occurring.

Operational costs can quickly escalate when call centers fail to optimize these metrics. High call arrival rates paired with low agent utilization rate or inefficient call handling can lead to increased call abandonment rate, longer wrap up time, and ultimately, dissatisfied customers. These operational inefficiencies not only frustrate customers but also erode profit margins and hinder revenue recognition. Implementing automated billing and streamlining center operations are proven ways to reduce manual errors, improve revenue efficiency, and ensure all customer calls are properly billed.

Key performance indicators (KPIs) such as calls answered, schedule adherence, and agent effort score are critical for evaluating team performance and identifying recurring issues. By focusing on these KPIs, call centers can optimize resource allocation, improve agent productivity, and enhance the customer effort score. This leads to more loyal customers, higher customer satisfaction, and stronger revenue collection functions.

To prevent revenue leakage and improve call center metrics, consider these actionable tips:

1. Implement Automated Systems: Use automated billing and invoicing to minimize manual errors and reduce operational inefficiencies.
2. Analyze Sales Data Regularly: Review sales data and call recordings to identify recurring issues and areas where revenue might be leaking.
3. Enhance Customer Interactions: Prioritize quality customer interactions to boost customer satisfaction and loyalty, driving more revenue.
4. Optimize Agent Utilization: Ensure agents are scheduled and utilized effectively to handle incoming calls, reducing call abandonment rate and improving agent effort score.
5. Provide Self-Service Options: Offer self-service options to empower customers, decrease call volume, and improve the customer effort score.

By closely tracking call arrival rate and call volume, and acting on these insights, call centers can significantly reduce revenue leakage, improve revenue efficiency, and deliver a better customer experience. Regular follow-ups, analysis of wrap up time, and monitoring of net promoter score will further help identify and fix revenue leaks, ensuring your call center remains competitive and profitable.

The Operational Ripple Effect

Missed calls result in more than revenue leakage. Operational strain builds as teams attempt to compensate, leading to increased callback volume, longer resolution times, and higher call abandonment rates. Customers are often forced to repeat themselves when reconnecting, which adds frustration and slows issue resolution. Complex queries can further increase resolution times and customer frustration, especially if not identified and addressed promptly.

At the same time, staff experience greater pressure as they juggle follow-ups alongside their regular responsibilities, increasing stress and burnout. The support team plays a crucial role in managing these follow-ups and maintaining service quality under such conditions. Without consistent call capture, businesses also lose critical insight into peak demand, caller intent, and marketing attribution, making it harder to staff effectively, optimize campaigns, and plan for growth. Understanding customer expectations and extracting valuable insights from call data are essential for optimizing operations and improving customer satisfaction.

Top 5 Call Performance Metrics

There is a bevy of additional KPIs that point to operational inefficiencies. These data-driven insights give you a clearer picture of what’s happening in consumer interactions, making it easier to improve the customer experience, help your employees work more efficiently, cut unnecessary costs, and make evidence-based decisions based on real trends instead of just guesswork. Here are a few tips to help you leverage these metrics for better call performance outcomes.

The five most important KPIs for measuring call performance include:

1. First Call Resolution (FCR)

What it measures: FCR tracks the percentage of customer issues resolved during the first interaction without the need for follow-up calls.

How it connects to missed calls/revenue leakage: When FCR is low, customers are more likely to call back, wait on hold, or give up entirely. Each repeat call increases the risk of abandonment, frustration, and lost revenue. Poor FCR also drives up call volume, making it harder for teams to answer new inbound calls and creating a ripple effect that leads to more missed opportunities.

Why it matters: Improving FCR reduces repeat calls, frees up agent capacity, and ensures high-intent callers get what they need the first time before they move on to a competitor.

2. Average Handle Time (AHT)

What it measures: Average Handle Time looks at how long agents spend on each call, including talk time, hold time, and after-call work.

How it connects to missed calls/revenue leakage: When AHT is too high, agents stay tied up longer, queues grow, and more callers abandon before reaching a live person. Those abandoned calls often represent lost sales, missed appointments, or unbooked services, all of which are direct contributors to revenue leakage.

Why it matters: A balanced AHT keeps calls moving without sacrificing quality. Lower handle times mean agents can answer more calls, reduce wait times, and capture more revenue from inbound demand.

3. Customer Satisfaction Score (CSAT)

What it measures: CSAT captures how satisfied customers are with a specific interaction or overall service.

How it connects to missed calls/revenue leakage: Missed or delayed calls often lead to low CSAT scores, even if the issue is eventually resolved. Customers who feel ignored or inconvenienced are less likely to return, refer others, or complete future transactions. This turns missed calls into long-term revenue loss.

Why it matters: CSAT helps you understand how missed calls and slow responses impact customer sentiment. Tracking it alongside call metrics reveals whether operational issues are quietly pushing customers away.

4. Call Abandonment Rate (CAR)

What it measures: Call Abandonment Rate shows the percentage of callers who hang up before reaching an agent.

How it connects to missed calls/revenue leakage: Abandoned calls are missed calls in real time. High abandonment rates often signal understaffing, long wait times, or poor call routing, all of which directly translate into lost revenue and missed high-intent leads.

Why it matters: CAR is one of the clearest indicators of revenue leakage risk. Every abandoned call is a customer who needed something and didn’t get it.

5. Net Promoter Score (NPS)

What it measures: NPS gauges customer loyalty by asking how likely someone is to recommend your business.

How it connects to missed calls/revenue leakage: Repeated missed calls, unanswered after-hours inquiries, or slow callbacks erode trust over time. Even if customers don’t complain, those negative experiences show up in lower NPS scores, resulting in fewer referrals, renewals, and repeat purchases.

Why it matters: NPS reflects the long-term cost of missed calls. It shows whether call handling issues are slowly damaging current sales along with your brand and future revenue.

How to Prioritize These KPIs

Start by focusing on the KPIs most closely tied to call accessibility and immediate revenue capture. Call Abandonment Rate and Average Handle Time should come first because they directly reveal whether customers are getting through or giving up.

From there, prioritize First Call Resolution to reduce repeat calls and prevent future congestion. CSAT and NPS should be used to measure the downstream impact, such as how missed calls and delays affect customer loyalty, retention, and referrals over time.

Revmo AI: Stopping Missed Interactions From Becoming Lost Revenue

Accurate call metrics are only valuable if every call is actually captured. Missed calls, after-hours inquiries, and inconsistent call handling create blind spots in reporting, making it nearly impossible to measure performance or prevent revenue leakage.

Revmo AI captures every call, even after hours, so no opportunity is missed. Our platform turns every interaction into accurate and actionable data, providing your business with a clear view of KPIs like abandonment rate, first call resolution, and handle time. This complete visibility enables your staff to spot gaps, improve performance, and stop revenue from slipping away.

With Revmo AI:

• Calls are answered 24/7, reducing abandonment and missed opportunities
• After-hours and overflow calls are captured, not lost
• Caller intent, outcomes, and trends are logged automatically
• Metrics reflect real demand, not staffing limitations

Stop letting missed calls distort your data and drain your revenue. Book a demo today to learn how Revmo AI helps you capture every call, measure what matters, and prevent revenue leakage.