Incident Metrics 101 - what are MTBF, MTTF, MTTR, and MTTA?

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    Home / Product / Incident Metrics 101 - what are MTBF, MTTF, MTTR, and MTTA?

    Performing within a certain time frame, with the highest efficiency level possible, may make or break your product or service. It is inevitable that there will be bumps along the way. Luckily, the hours of operation culminate in real-time data that will help you with the incident management process.

    These key indicators, namely the incident management KPIs, will provide invaluable insight into the piece of equipment you use, the efficiency of incident response team, and how the customers' reception of the product or service change over time.

    In this article, we'll cover what the incident metrics are, the areas you can monitor, and how to calculate them. Let's go!


    • MTBF (mean time between failures), MTTR (mean time to respond), MTTF (mean time to failure), and MTTA (mean time to acknowledge) are incident metrics that help businesses track their goals and shortcomings.
    • MTBF is helpful in assessing the reliability and performance of a product or service while MTTR evaluates team efficiency in repairing a system.
    • While MTTR focus on the average time needed to repair a product or system, MTTF measures and estimates the average lifetime of a product before it fails entirely; hence, the need for replacement.
    • MTTA is a good metric for bridging the gaps between your team and customers because it focuses on average time taken to acknowledge a customer’s request and take appropriate actions to solve the issues.

    What Are Incident Metrics?

    Incident metrics cover a wide range of key performance indicators (KPIs) or data to monitor the performance of internal teams and services offered by a business. Companies track these metrics to evaluate their goals, see their progress, SLAs, and adjust timelines.

    Additionally, these metrics help identify and fix disruptions (aka incidents) in your entire operation. That is why it is important to pay attention to incident management as the process reveals problems with possible adverse impact on your business, and it ensures maintaining the service quality.

    incident metrics timeline

    Mean Time Between Failure (MTBF)

    MTBF (mean time between failure) is the metric that measures the average time between failures of something (usually a technology product) that can be repaired. It is a critical metric when tracking the performance and reliability of a product. Higher time periods between failures suggest more reliability of the product.

    How to calculate MTBF

    MTBF is calculated by adding up all the data from the period of time you want to calculate and dividing by the number of failures.

    To put it into perspective, let's say that you want to assess the 24-hour data and there were four hours of downtime in four different incidents. Your total uptime is 20 hours. Therefore, the MBTF would be:

    MTBF= 20 / 4

    So, your MTBF is 5 hours. In other words, your system stayed up, on average, for 5 hours before a crash happened.

    The use cases of MTBF

    MTBF is one of the key performance indicators that assesses the maintainability of repairable items. It tells the buyers whether the product or system is reliable enough to invest in. It informs the maintenance teams about the issues and problems that need fixing.

    This metric also helps companies recommend upgrades, replacements, or maintenance to customers.

    Mean Time to Recovery (MTTR)

    MTTR (mean time to recovery, respond, resolve, restore, or repair) is one of the key metrics used for measuring the average time it takes to repair a product or system. It consists of the entire time period it takes to discover, recover, and test until the product is fully functional again.

    How to calculate MTTR

    To calculate MTTR, you can add up the total repair times spent during any specific period, then divide that by the number of repairs.

    For example, let's say that you want to look at daily repairs. In the meantime, there were 10 outages and the repair process took 6 hours. 6 hours is 360 minutes. Therefore, the MTTR is:

    MTRR = 360 / 10

    So, your MTTR is 36 minutes. In other words, it took, on average, 36 minutes to fix the issues and function properly. For an ITOps or DevOps team, it is crucial to stabilize the MTRR to the absolute minimum to keep everything smooth.

    The use cases of MTTR

    MTTR is usually used for tracking repairs. Keeping the MTTR as low as possible increases team efficiency as well as streamlining the entire repair process.

    Mean Time to Failure (MTTF)

    MTTF (mean time to failure) is an indicator of reliability. It shows how long it takes for a device to fail. To put simply, it is the average time or lifespan of products or services. Because the devices must be replaced after failure, MTTF is used for non-repairable items.

    This measure helps you understand how long a system will likely last, determines whether a new version of an existing system is performing better than its predecessor, and gives you insight into when to expect maintenance checks on your systems. Basically, it helps companies make informed decisions to fix internal problems and inventory management.

    mean time to failure metric

    How to calculate MTTF

    You can calculate MTTF by adding up the lifespans of all devices and dividing that by the number of devices you have.

    Let's say that you produce smart phones and want to find out the MTTF of their batters. Three of these batteries lasted for 4.5, 3.7, 5.1 years respectively, so:

    MTTF= (4.5 + 3.7 + 5.1) / 3

    Your mean time to failure rate is ~4.43 years. 

    The use cases of MTTF

    It is important to keep in mind that MTTF is exclusive to non-repairable items, meaning that this metric entails complete failure and the product or service must be replaced.

    Generally speaking, MTTF is used to measure the average lifetime of a product, especially if it has a short lifespan. It helps understanding what causes full product failure as well and suggests new materials or providers should be chosen for future productions if MTTF is shorter than expected.

    Mean Time to Acknowledge (MTTA)

    MTTA (mean time to acknowledge) refers to the average time it takes to acknowledge a problem and taking necessary action to fix the issue. This metric is both helpful for evaluating the alerting capabilities of an organization’s internal teams and the effectiveness of its alert systems. By tracking this metric, you can optimize your process and increase customer satisfaction.

    How to calculate MTTA

    You can calculate your MTTA by adding up the average time between detection and acknowledgement, the dividing that number by the total number of incidents.

    Let's imagine for a moment that you had 5 incidents and a total of 40 minutes elapsed between acknowledging the issue and working on fixing for all 5. Divide 40 by 5 and voila! You get 8 minutes MTTA.

    The use cases of MTTA

    MTTA is particularly useful for DevOps teams and other support teams. It reflects the effectiveness of responsiveness to a failure. It also helps keep MTTR low and customers happy, which is to say that MTTA ensures customers that their issues are acknowledged promptly and they are prioritized, regardless of the time to resolution.

    Frequently Asked Questions

    What are incident metrics?

    Incident metrics include MTBF (mean time between failure), MTTR (mean time to recovery, respond, resolve, restore, or repair), MTTF (mean time to failure), MTTA (mean time to acknowledge).

    What is MTTR and MTTA?

    MTTR refers to the mean recovery time spent on repairing a product or service. MTTA is the average time it takes to acknowledge and work on minor or major incidents that need fixing.

    How do you calculate MTTR incidents?

    To calculate MTTR, you can add up the total repair times spent during any specific period, then divide that by the number of repairs.

    What is MTTR and MTTF?

    MTTR is the mean time to recovery, respond, resolve, restore, or repair. MTTF is the mean time to failure.

    What is the difference between SLA and KPI?

    KPIs (key performance indicators) provides insights into the efficiency of company-wide goals and actions taken while SLA (service legal agreement) ensures the sustainable performance of service level metrics, keeping them above certain metrics criteria. 

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