Expectancy Theory of Motivation

The expectancy theory was proposed by Victor Vroom of Yale School of Management in 1964. Vroom stresses and focuses on outcomes, and not on needs unlike Maslow and Herzberg. The theory states that the intensity of a tendency to perform in a particular manner is dependent on the intensity of an expectation that the performance will be followed by a definite outcome and on the appeal of the outcome to the individual.

This theory is meant to bring together many of the elements of previous theories. It combines the perceptual aspects of equity theory with the behavioral aspects of the other theories. Basically, it comes down to this "equation":

M = E*I*V

Or   

Motivation = Expectancy * Instrumentality * Valence

M (motivation)= is the amount a person will be motivated by the situation they find themselves in. It is a function of the following.

E (expectancy) = The person's perception that effort will result in performance. In other words, the person's assessment of the degree to which effort actually correlates with performance.

I (instrumentality) = The person's perception that performance will be rewarded/punished. i.e., the person's assessment of how well the amount of reward correlates with the quality of performance. (Note here that the model is phrased in terms of extrinsic motivation, in that it asks 'what are the chances I'm going to get rewarded if I do good job?'. But for intrinsic situations, we can think of this as asking 'how good will I feel if I can pull this off?').

V (valence) = The perceived strength of the reward or punishment that will result from the performance. If the reward is small, the motivation will be small, even if expectancy and instrumentality are both perfect (high).