TL;DR: Load and performance testing produces a vast amount of data. This data has to be interpreted and communicated. Because not every interested party speaks the same language, Xceptance developed a performance test rating and grading system. It evaluates response time, stability, and predictability and transforms three factors into a simple and communicable form. While doing that, it does not compromise on quality. It has been successfully used in more than 400 projects.
The Challenge
Load and performance testing is a key activity for making an online business successful. It validates that traffic and conversion expectations can be fulfilled. This of course applies to all kinds of Internet-based applications. Basically, as soon as there are expectations in terms of stability and performance, a test is mandatory to validate these. Expectations are usually set as requirements by different organizational groups such as sales, product management, engineering, and development teams.
Every group has a different understanding when it comes to results, goals, and success criteria. Some might be more concerned with the business impact, others are looking for technical implications of design decisions, and some just want to improve performance.
The group that is tasked with the evaluation of the requirements is faced with a very wide range of success definitions. In addition, it has to explain its technical measurements to all participating parties so that each party easily understands the state of testing.
Engineers rather look for detailed metrics including but not limited to the system behavior under test, while business-centric stakeholders just expect a clear yes or no. But performance testing typically does not deliver a clear result.
How can one reach all target groups without causing too much extra work to cater to all individual needs?
The Rating System
Xceptance developed a rating system that uses an American education system-like grading from A to F. The grades A to C symbolize a pass, while D and F are considered a fail. A grade B stands for an assumed average across similar customers and projects. It also stands for a good result. This leaves room in both directions to over or underperform.
Because performance results are not just shaped by response times, three factors are taken into account:
- Response Times
- Errors
- Predictability

Before continuing a detailed discussion of the factors, this table explains each grade in one sentence. For the more ambitious customers, the A+ stretch goal was added.
Let’s talk about our three factors in detail now.
Continue reading Performance Test Rating Criteria