Service level indicators

B2B customers want more than vague promises like “fast response times” or “industry-leading availability.” They want a quantifiable way to know if you can deliver on those promises or if your customer support needs work.

Service level indicators (SLIs) solve this problem by turning empty gestures into concrete, measurable standards. They give both sides of the contract an objective view into what service quality really looks like.

What are service level indicators?

An SLI is a specific metric that tracks the quality of service provided to customers. An SLI is used to define measurable performance standards, giving B2B companies and their clients a shared reference point for objectively evaluating service quality.

SLIs often appear in site reliability engineering and DevOps contexts, where common metrics include the success rate of HTTP requests, the percentage of successful 2xx status codes versus failed 5xx status codes in HTTP responses, or latency rates. Availability and uptime are also classic SLI examples in infrastructure monitoring.

Beyond technical engineering benchmarks, teams use customer service metrics like response time, resolution time, and escalation rate to stay accountable to clear, customer-facing performance benchmarks.

SLO vs. SLA vs. SLI

SLIs are tightly linked to service level agreements (SLAs) and service level objectives (SLOs), which makes them easy to confuse with each other. Here’s a breakdown of the core differences:

• SLIs are the measurements themselves: specific, quantifiable metrics like response time or resolution rate that reveal how a service is performing at any given time.
• SLOs are the thresholds companies and clients work together to define for particular SLIs, such as a response time of four hours or less for 95% of tickets.
• SLAs encode SLOs into a formal, binding document, together with the consequences of falling short of SLO targets. SLAs promote accountability by outlining exactly what customers expect of service providers and what happens when performance doesn’t hit the mark.

Common service level indicator metrics

The most useful customer service SLIs measure service expectations that B2B customers actually experience and care about. Some of the most common SLI metrics that fit the bill include:

• Response time: Response time measures how quickly a support team makes the first reply after a customer sends in a question or concern.
• Resolution time: This SLI focuses on how long it takes to fully resolve a customer inquiry, from initial contact to final resolution and everything in between. It’s a more holistic SLI than response time alone because it measures not just how fast teams respond, but how efficient (or not-so-efficient) the entire resolution process is.
• Average handle time (AHT): The AHT metric looks at how much time support teams spend actively engaged in solving a customer inquiry, including talk time, hold time, and after-call work. Unlike with resolution time, waiting time isn’t part of AHT.
• Escalation rate: Escalation rate tracks the percentage of support tickets that get sent to a higher tier. A consistently high escalation rate can point to problems with unclear ownership or gaps in frontline training.
• SLA compliance rate: SLA compliance tracks how often your team is hitting the SLOs outlined in an SLA. For example, if your SLA promises a four-hour response time and your team delivered on that promise 97 times out of 100 last month, that’s a 97% SLA compliance rate.