Expectancy (valence - instrumentality - expectancy) theory also helps managers understand the relationship between motivation and pay. According to Tolman and Vroom's expectancy theory, motivation depends on the expectation that effort will produce performance. Humans form a mental picture about the likelihood that a given level of effort will result in a desired outcome. Various outcomes have different levels of desirability or valence. A direct application of expectancy theory to compensation is the idea of earning days of vacation or sick leave. Workers can look in the employees' handbook and see that if they remain with the company five years, ten vacation days per year will be earned; staying ten years results in an additional five vacation days a year, and so forth. At the same time, they will become senior employees, earning other desired out-comes, like annual raises a concept called the instrumentality of goal-directed behavior.