Application Stability Assessment: Why It’s Your Most Critical Investment in 2021

An application is only as strong as its code. More specifically, it’s only as strong as how its code consistently behaves in response to user action. 

Application stability management (ASM) determines whether your code is working the way you intended. This is essential for any application’s success, regardless of its audience. Developers should incorporate ASM during the software development life cycle (SDLC) instead of at the end of development. This can prevent the last-minute, panic-inducing detection of that show-stopping flaw just before release.  

Application Stability Management vs. Application Performance Management

Application performance management and application stability management are often confused or blended. There is a distinct difference between the two. 

Application performance management looks at the code’s infrastructure. Is the code landscape stable? 

Application stability management looks at the code’s expression. Is the code itself reliable? In other words, is the code working the way it’s intended to? 

DevOps teams (those responsible for automating and integrating processes between the software development teams and IT) care a lot about application performance management. Software development teams care a lot about application stability management because they want to know if their code is working properly and as expected. 

Why is Application Stability Important?

Customer satisfaction doesn’t exist within the confines of their experience with an actual product or service itself—it extends to their digital experience with the application that facilitates that product or service. Their satisfaction starts with that digital experience.

Recognition of the importance of application stability is increasing as B2B and B2C organizations ramp up their digital transformation. Applications are now a vital part of any product or service because they are the fulcrum for product and service presentation and delivery. If that fulcrum repeatedly fails or does not work smoothly, the whole development process falls apart. 

Customers can now broadcast any application defects through social media and application reviews, which can instantaneously dissuade thousands of potential customers from using your application in mere seconds. 

You need to include application stability assurance in your development process. If your application doesn’t work correctly every time, all the time, it’s nothing but a liability. 

Application Stability Metrics (ASM): Measuring Your Application’s Stress Management Skills

Usability Testing

Usability testing shows you how easy your application is to use by both novice and experienced users. Experts recommend testing at least 20 users. 

But, how is usability defined with regard to the user interface? For the user experience to be meaningful and valuable, the information must meet the following criteria, which can be found on usability.gov:

  • Useful: Your content is original and fulfills a need
  • Usable: The site must be easy to use
  • Desirable: Design elements and advertising elements (image, identity, and brand) successfully evoke emotion and appreciation
  • Findable: The user can navigate content and locate the content onsite and offsite
  • Accessible: Content is fully accessible to people with all disabilities
  • Credible: Users find you trustworthy based on what you tell them on the site 

There are numerous user metrics you can use to test your application. Several of the key metrics are listed below, but other usability metrics can be found here:

  • Success rate – Can the user perform the task (yes/no)?
  • Duration – How long did the task take to complete?
  • Error rate 
    • If only one error is possible for each task, measure Error Occurrence Rate (divide the number of errors that occurred for all users by the number of errors possible). 
    • If multiple errors are possible for a given task, use Error Rate (divide number of errors by the total number of attempts) 
  • Subjective satisfaction
    • System Usability Scale (SUS)
    • Net Promoter Score (NPS)
    • Customer satisfaction (CSAT) 

Performance Testing

Performance testing measures the application’s speed, stability, and responsiveness when the application is under stress (i.e., varying workload conditions). Software under stress responds in a similar manner to the way our bodies under stress respond: efficiency and effectiveness decrease. Stress is inevitable, however. That is why ASM performance testing must be included in any development process. 

Performance testing also measures an application’s resource usage, reliability, and scalability.  

Common types of performance tests include: 

  • Load and volume testing: How will the application behave when many users are using it? Evaluate your application’s behavior while simulating the expected peak volume of users. To measure load, divide the total number of concurrent users by a set time. Monitoring performance during the test will enable you to identify problems and bottlenecks your application may experience. 
  • Stress testing: After you conduct a load test, you should conduct a stress test. This test measures the upper limits of the application’s capabilities with regard to scalability and breaking points by pushing it beyond the expected peak user levels used in the load testing. It can also identify risk factors. When you see how users handle errors, you can improve the customer experience.
  • Soak testing: Soak testing is a type of load testing. It’s also known as capacity testing and longevity testing. Similar to load testing, you place the application under stress, but you do it for a predetermined extended time period for soak testing. 
  • Spike testing: Spike testing measures how well an application performs in response to sudden increases and decreases in user volume. It also measures recovery time (how quickly and how well the application stabilizes between user volume spikes).

Interruption Testing

How will your application respond under pressure? Imagine you are giving an important technical presentation in front of a large audience, and someone keeps interrupting you to ask random questions. How well do you respond to these interruptions? How quickly can you accurately get back on track and pick up where you left off? 

Applications experience this scenario constantly. But for applications, interruptions include incoming phone calls, text messages, notifications from other applications, alarms, dropped network connectivity, and subsequent recovery. It even matters if the device is plugged in or charging because these are all interruptions that can get the application off track. Optimally, the application should run seamlessly in the background and return to its state previous to the interruption. 

Interruption testing, then, is a type of functional testing that measures how well the application does when it is distracted by other signals within the device. It is not the same as recovery testing, which measures how well the application recovers after being shut off. 

Compatibility Testing

Users interact with many applications on several different types of devices (e.g., phone, tablet, desktop). Compatibility testing measures how well the application performs across all devices. Many things can break in an application when it’s used across multiple devices. That’s why compatibility testing is so important.

Elements to test across devices:

  • Content: How does the content appear on a desktop compared to mobile devices with varying screen sizes?
  • Navigation: How should mobile navigation differ from desktop navigation?
  • Font and objects: How will these be modified to adjust to different screen sizes?

Localization Testing

Localization testing measures software performance in different geographic locations. Different locations have different cultural norms, bandwidths, languages, and dialects. In other words, how well are the user interface, default language, currency, date, time format, and documentation performing in the targeted location? Is it ready to use in this location? 

Content and user interface are the most important elements of localization testing. With localization testing, a group of test users familiar with that geographic location will test the application and document elements such as: 

  • Are there typographical errors? 
  • Is the user interface culturally appropriate?
  • Are there linguistic errors?

Reliability Testing 

Reliability testing measures how long an application performs perfectly. Stability and recovery testing are both types of reliability testing. Stability testing identifies data leaks or areas where data leaks could occur. Recovery testing measures how much time it takes the application to recover after a system failure. 

Functional Testing

Does your application do what it is supposed to do? In other words, is the code behaving correctly in every circumstance? Once you’ve determined the primary objective and flow of your application, you need to ensure that the application features meet your specifications in a highly responsive manner. Functional testing can also test your application’s launch and installation behavior as well as the fluid flow of sign-up and login procedures. 

Manual vs. Automated Application Stability Assessment

Humans perform manual stability testing. Automation frameworks or other software perform automated stability testing. 

You can conduct organic exploratory testing with manual testing, but not with automated testing. For example, when human testers discover issues, they can explore them organically (without a predefined script). Manual testing is more cost-effective than automated testing. Manual testing is an excellent choice for projects with both low and high-volume regression. 

Manual testing is also more agile and able to navigate naturally through changes to the user interface. With automated testing, when the slightest change is made to the user interface, such as a change in the ID or class of a button, you must change the automated test scripts for the tool to work properly. 

There’s also a lot to be said for a human evaluating the human experience, instead of using an automation tool to gauge the user-friendliness of a product. When you do manual testing, you have humans talking to humans. This produces insightful comments about customer experience attitudes. 

Your  application can be your greatest success, especially when you fortify it with application stability testing.