Baseline is a process of capturing performance metric data for the sole purpose of evaluating the efficacy of successive changes to the system or application. It is important that all characteristics and configurations except those specifically being varied for comparison remain the same, in order to make effective comparisons as to which change (or series of changes) is the driving result towards the targeted goal. Armed with such baseline results, subsequent changes can be made to system configuration or application and testing results compared to see whether such changes were relevant or not. Some considerations when generating baselines include:

Load testing is the process of putting demand on a system and measuring its response; that is, determining how much volume the system can handle. Stress testing is the process of subjecting the system to unusually high loads far beyond its normal usage pattern to determine its responsiveness. These are different from performance testing whose sole purpose is to determine the response and effectiveness of a system; that is, how fast is the system. Since load ultimately affects how a system responds, performance testing is almost always done in conjunction with stress testing.