Expectancy theory is about the mental processes regarding choice, or choosing. It explains the processes that an individual undergoes to make choices. In the study of organizational behavior, expectancy theory is a motivation theory first proposed by Victor Vroom of the Yale School of Management.
"This theory emphasizes the needs for organizations to relate rewards directly to performance and to ensure that the rewards provided are those rewards deserved and wanted by the recipients." 
Victor H. Vroom (1964) defines motivation as a process governing choices among alternative forms of voluntary activities, a process controlled by the individual. The individual makes choices based on estimates of how well the expected results of a given behavior are going to match up with or eventually lead to the desired results. Motivation is a product of the individual’s expectancy that a certain effort will lead to the intended performance, the instrumentality of this performance to achieving a certain result, and the desirability of this result for the individual, known as valence.
[hide] 1 Author
2 Key elements 2.1 Expectancy: Effort → Performance (E→P) 2.2 Instrumentality: Performance → Outcome (P→O)
2.3 Valence- V(R)
3 Current Research 3.1 Management
3.2 Computer Users
3.3 Models of Teacher Expectancy Effects
5 Related Theories
7 Further reading
In 1964, Vroom developed the Expectancy theory through his study of the motivations behind decision making. His theory is relevant to the study of management. Currently, Vroom is a John G. Searle Professor of Organization and Management at the Yale University School of Management.
 Key elements
The Expectancy Theory of Motivation explains the behavioral process of why individuals choose one behavioral option over another. It also explains how they make decisions to achieve the end they value. Vroom introduces three variables within the expectancy theory which are valence (V), expectancy (E) and instrumentality (I). The three elements are important behind choosing one element over another because they are clearly defined: effort-performance expectancy (E>P expectancy), performance-outcome expectancy (P>O expectancy).
Three components of Expectancy theory: Expectancy, Instrumentality, and Valence
1. Expectancy: Effort → Performance (E→P)
2. Instrumentality: Performance → Outcome (P→O)
3. Valence- V(R)
 Expectancy: Effort → Performance (E→P)
Expectancy is the belief that one's effort (E) will result in attainment of desired performance (P) goals. Usually based on an individual's past experience, self-confidence (self efficacy), and the perceived difficulty of the performance standard or goal. Factors associated with the individual's Expectancy perception are self efficacy, goal difficulty, and control. Self efficacy is the person’s belief about their ability to successfully perform a particular behavior. Goal difficulty happens when goals are set too high or performance expectations that are made too difficult are most likely to lead to low expectancy perceptions. Control is one's perceived control over performance. In order for expectancy to be high, individuals must believe that they have some degree of control over the expected outcome.