Among the many factors that influence expectancy, such as ability or interest, perception is perhaps the most significant factor. Perception is the engine that drives the belief of effort, performance, and outcome. Thus, if any one condition is perceived that it will be low, motivation will be low - just as the bond between links affects the chain. Because beliefs can vary, however; a subjective probability formula that is multiplicative in nature is used to more accurately measure expectancy and arrive at a predicted motivational force (represented as a number). The higher the number, the higher the motivation, with each component having its own probability range.