Goal setting involves the development of an action plan designed in order to motivate and guide a person or group toward a goal. Goals are more deliberate than desires and momentary intentions. Therefore, setting goals means that a person has committed thought, emotion, and behavior towards attaining the goal. In doing so, the goal setter has established a desired future state which differs from their current state thus creating a mismatch which in turn spurs future actions. Goal setting can be guided by goal-setting criteria (or rules) such as SMART criteria. Goal setting is a major component of personal-development and management literature. Studies by Edwin A. Locke and his colleagues, most notably, Gary Latham have shown that more specific and ambitious goals lead to more performance improvement than easy or general goals. The goals should be specific, time constrained and difficult. Vague goals reduce limited attention resources. Unrealistically short time limits intensify the difficulty of the goal outside the intentional level and disproportionate time limits are not encouraging. Difficult goals should be set ideally at the 90th percentile of performance,assuming that motivation and not ability is limiting attainment of that level of performance. As long as the person accepts the goal, has the ability to attain it, and does not have conflicting goals, there is a positive linear relationship between goal difficulty and task performance. The theory of Locke and colleagues states that the simplest, most direct motivational explanation of why some people perform better than others is because they have different performance goals. The essence of the theory is: Difficult specific goals lead to significantly higher performance than easy goals, no goals, or even the setting of an abstract goal such as urging people to do their best. Holding ability constant, and given that there is goal commitment, the higher the goal the higher the performance.