The above degradation mechanisms are determined by the change in the electrochemically active surface area (ESA or ECA) and the activity in the oxygen reduction reaction (ORR) before and after stress testing. As a result, the material would be considered more stable if less of its electrochemical characteristics decreased after the stress testing. Stress testing mainly involves the stimulation of a catalyst over a period of time and examines how the catalyst will behave under real-world conditions . As mentioned earlier in the kinetics section, the kinetics of a catalyst will decrease over time, and this is measured mainly by looking at the MSA of the current-voltage polarization curve. For a scientist to determine the durability of a catalyst in a fuel cell, it would typically take several months or years, which is costly and time-consuming. However, the time and cost would be substantially reduced with the availability of stress testing, also known as accelerated testing. During the stress testing process in Figure , researchers cycled between high and low voltages; however, the time frames were reported as hours instead of cycles. Because the Pt-based catalyst dissolves at high voltage and platinum deposits at low voltage, cycling this process thousands of times will accelerate the degradation mechanism that happens on the platinum catalyst and visualize how fast the surface area of the platinum will decrease. As a result, researchers will comprehend the durability of the catalyst in days rather than months, reducing the cost and time to determine the durability of catalysts, illustrated in Figure , as the ECA of the platinum catalyst slowly deteriorates after hours have passed in AST.