KPI for Software Testing: Essential Metrics for Quality Assurance

Key Performance Indicators (KPIs) are important to define and track wherever we can. A key area of the software development cycle that is often overlooked is the testing process. Software testers play a crucial role in evaluating these KPIs and maintaining product quality. From creating a suite of automated end-to-end tests to manual testing, teams of all sizes can improve their ability to decrease the likelihood of bugs reaching users. Additionally, software testing metrics are essential tools for assessing the quality and effectiveness of testing processes. Tracking test execution time is crucial for evaluating the efficiency of the testing process.

Understanding Software Testing KPIs

In the realm of software testing, Key Performance Indicators (KPIs) are indispensable tools that help teams gauge the effectiveness and efficiency of their testing processes. By quantifying various aspects of the testing process, KPIs provide valuable insights that drive data-driven decisions, ultimately enhancing the quality of the software product. Whether you’re dealing with manual testing or automated tests, understanding and leveraging KPIs can significantly improve your testing efforts and test efficiency.

Definition of Key Performance Indicators (KPIs) in Software Testing

Key Performance Indicators (KPIs) in software testing are quantifiable measures that assess the performance and effectiveness of the testing process. KPIs can also assess the effectiveness of test design in the testing process. These indicators offer a clear picture of how well the testing team is performing, highlighting areas that need improvement and ensuring that the software testing process aligns with the overall goals of the project. By tracking KPIs, teams can make informed decisions that enhance the quality assurance process and ensure that the software meets the desired standards.

Importance of KPIs in the Software Testing Process

KPIs are vital in the software testing process for several reasons:

Evaluating Testing Efforts: KPIs help in assessing the effectiveness of the testing efforts, ensuring that the testing process is thorough and comprehensive.
- KPIs can also help in assessing the thoroughness of 'test review' processes.
Identifying Areas for Improvement: By analyzing KPIs, teams can pinpoint specific areas that require enhancement, leading to continuous improvement in the testing processes.
Measuring Software Quality: KPIs provide a clear measure of the software’s quality, helping teams ensure that the product meets the required standards before it reaches the users.
Optimizing Resources: Tracking KPIs allows teams to allocate resources more efficiently, ensuring that the testing efforts are both effective and economical.
Enhancing Collaboration: KPIs foster better communication and collaboration among team members, ensuring that everyone is aligned with the testing goals and objectives.

Where to start

For smaller teams, manual testing is a good place to start. The process is simple, developers deploy their changes to a testing environment and invite coworkers to act as a real user would, ensuring that there are no defects found. Everyone can help in this process from testing engineers, product and project managers, designers, and executives; a good side effect of including more people is that everyone stays up-to-date with the product.

Larger teams with more resources can devote time to creating a suite of automated tests that cover a multitude of test cases. This can take a lot of time and coding expertise. Although there are products available that make this process easier, they can get pricy as your number of tests increase. Tracking the number of tests executed, both manual and automated, is crucial for assessing testing effectiveness and overall quality assurance outcomes. Unlike other forms of automation, automated tests can become stale as your product changes; you will want to devote several hours a month to maintaining the quality of your test suite so that you do not run into false positives and difficulties deploying your changes to production.

Types of Software Testing Metrics

Software testing metrics are essential tools that provide insights into the effectiveness and efficiency of the testing process. These metrics can be broadly classified into two categories: absolute metrics and derivative metrics.

Absolute Metrics: These are straightforward, quantitative measures that offer a clear picture of the testing process. Examples include the number of test cases executed, defects found, and test coverage. Absolute metrics provide raw data that can be directly observed and measured, making them fundamental to understanding the basic performance of the testing efforts.

Derivative Metrics: These metrics are calculated from absolute metrics and provide a more detailed analysis of the testing process. Examples include defect density, test efficiency, and test effectiveness. Derivative metrics offer deeper insights by combining multiple absolute metrics, helping teams to identify trends and areas for improvement.

By leveraging both absolute and derivative metrics, testing teams can gain a comprehensive understanding of their testing processes, enabling them to make data-driven decisions that enhance software quality.

Easy key performance indicators to start with

Total number of tests / number of test cases

Tracking the number of test cases executed helps in assessing the effectiveness and quality of the testing process, as more test cases executed will roughly translate into decreasing the total number of defects that reach your users. Start with at least one test case and gradually increase the number of test cases as the product matures. Unless your product is in a highly regulated space, you may run into the law of diminishing returns and end up slowing down the testing process which hurts your software team’s efficiency.

Effective test case design is crucial in ensuring the effectiveness and quality of the testing process.

Number of defects reaching production

Users hate bugs and you should as well. It is vital to proactively monitor the health of your applications and record the number of defects that reach production. Over time, your testing process should limit the number of bugs that reach your users in production. Bugs happen so don’t if one slips out, but you will want to do your best to prevent these issues in the testing phase of your development cycle. Effective defect resolution is crucial in minimizing the number of defects that reach production.

The time it takes to finish the testing process

Deployments should happen quickly, with test execution time being a key factor in ensuring quick deployments. It is common for the testing process to take multiple days as multiple stakeholders may need to sign off before code reaches production. You will want to cut down this time to be as nimble as possible. Track the amount of time it takes to test just like you record the amount of time it takes to develop new features.

Difference Between Metrics and KPIs

While metrics and KPIs are often used interchangeably, they serve distinct purposes in the software testing landscape:

Metrics: These are quantitative measures that provide insights into specific aspects of the testing process. Examples include test coverage, defect density, and test execution time. Metrics offer raw data that can be analyzed to understand various facets of the testing process.
KPIs: Key Performance Indicators are derived from metrics and are used to evaluate the performance of the testing process against specific goals and objectives. KPIs are more strategic, providing a higher-level view of how well the testing efforts are aligning with the overall project goals.

Understanding the difference between metrics and KPIs is crucial for effectively managing and optimizing the software testing process.

Creating your manual testing process

There is no reason to overcomplicate manual testing; this is the simplest form of testing but it can also be the most effective. You should move through the application as a user would, trying to ensure that all edge cases are covered. Remember that users do not always travel down the happy path that you would assume. For inputs, try putting in characters instead of numbers, inputting long strings that might break the UI, and other weird behavior (people love emojis).

Test case design is crucial in creating an effective manual testing process. Just like automated tests, software testers can define and run a list of test cases that you continually run through with each change. These should be flows like registering as a new user, logging in as an existing user, and processes that ensure that the overall integrity of your application is intact. Whether you are a test engineer, project manager, or an executive, you are part of the testing team. It may take more time but your users and engineers will be happy that costly defects are found before they cause trouble.

Define your testing tasks clearly. Maybe certain members of your team are more proficient in certain areas of your products than others. We all want to make our software as good as possible but try to keep new suggestions to a minimum; if something is worth noting, consider them as future improvements as long as they are not critical defects.

If possible, try to ensure that someone is the lead tester, or test manager for the change. This will typically be the product / project manager in charge of the product. It is easy to have too many cooks in the kitchen when it comes to testing.

Essential KPIs for Software Testing

Defect Detection and Resolution

Effective defect management is a cornerstone of quality assurance in software testing. Here are some essential KPIs that focus on defect detection and resolution:

Defect Detection Rate: This KPI measures the number of defects detected during testing as a percentage of the total number of defects. A high defect detection rate indicates a thorough testing process.
Defect Resolution Rate: This KPI measures the number of defects resolved as a percentage of the total number of defects. It provides insights into the efficiency of the defect resolution process.
Defect Density: This KPI measures the number of defects per unit of code or functionality. It helps in identifying areas of the software that are more prone to defects, enabling targeted improvements.
Defect Leakage Rate: This KPI measures the number of defects that escape detection during testing and are found in production. A low defect leakage rate indicates an effective testing process that catches most defects before the software reaches the users.

By tracking these KPIs, the testing team can optimize their efforts, ensuring that defects are detected and resolved efficiently, thereby improving the overall quality of the software product.

Defect Density

Defect Density is a key performance indicator that measures the number of defects relative to the size of a software module. This metric is crucial for identifying areas of the software that are more prone to defects, enabling targeted improvements.

The formula for calculating Defect Density is: Defect Density (DD) = Number of Defects / Size of Module

For example, consider a software application with three modules, each with the following number of identified defects and lines of code (LOC):

Module 1: 10 defects, 1000 LOC

Module 2: 20 defects, 1500 LOC

Module 3: 10 defects, 1000 LOC

The total number of defects is 40, and the total LOC is 3500. The Defect Density is calculated as: Defect Density = 40 / 3500 = 0.01142

By monitoring defect density, teams can focus their efforts on the most problematic areas, improving the overall quality of the software.

When test cases are more trouble than they are worth

Your development team wants to move fast. Try to be as efficient as possible with your testing processes. A long testing cycle slows the pace of product development and can cause unfortunate downstream effects as code piles up and deadlines start to slip away. Effective test case design can help avoid unnecessary stress for the team.

If your product has not gone through several rounds of testing before, you will find bugs. If the bugs do not pertain to the change you are testing, create a note for your development team and keep moving through your test process.

How to handle failed test cases

Over time, test cases will become stale and you will run into failed tests. If you have done an effective job creating valid test cases, then a failed test case will often mean a new bug has been introduced to your product. You should rectify this issue before releasing the change to production.

However, if you find yourself removing or changing these tests constantly as they fail, it might be a good sign that your test cases are not as effective as possible. Test execution is a key factor in determining the effectiveness of the testing process. It is easy to fall into the trap of creating tests so that your total number of test cases is impressive. This will slow down your development process and cause unnecessary stress for your team.

Quality assurance teams

If you have the budget, consider hiring quality assurance engineers, often referred to as test engineers. These engineers are specialized in creating effective testing procedures and guiding your team in creating test cases and unit tests. Quality assurance engineers can become some of the most effective members in your development team as they act as the first line of defense against critical defects reaching your customers. Test review is a crucial part of their role, ensuring that all test cases are thoroughly evaluated and optimized.

Treat your QA engineers well. They will save you time and time again. The decision to pursue full-time test engineers depends on your budget and worries around pushing bugs to production. Highly regulated industries like healthcare and certain areas of finance might require that you invest in building out QA teams, you will need to evaluate what is best for your situation.