• Expectancy: Is a person who believes that a job-related effort will lead to an acceptable performance. Expectancy is based on probabilities and ranges from zero to one, if an employee is completely sure that his target will be achieved, the expectancy has a value of one.

• Instrumentality: Is an individual’s estimate of the potentiality that an achieved task performance can lead to several work outcomes. Also, the instrumentality ranges from zero to one. For instance, if an employee considers that a good performance rating will always result in a salary increase, the instrumentality here has a value of one.

• Valence: Is when an employee appreciates the value of a reward. Such as salary increase, recognition, financial or non-financial rewards and other rewards might have more or less value to an employee. Dissimilar to Expectancy and Instrumentality, Valence can be either positive or negative. If an employee has the advantage of attaining a reward, valence is positive and vice versa. Yet, if an employee is indifferent to rewards, valence is zero, where the total range is from minus one to plus one. Theoretically, a reward has a valence because it is related to an employee’s need. Therefore, valence provides a link to the content theories of motivation (Maslow, Herzberg, McGregor and Aldefer).

Vroom suggests that Motivation, Expectancy, Instrumentality and Valence are related one to another by the following equation:

Motivation = Expectancy x Instrumentality x Valence

The effect in the equation is considerable, where it shows that motivation is always affected by the range of Expectancy, Instrumentality and Valence. In addition, the multiplier assumption implies that if one of these three factors is zero, the overall level of the motivation will be zero.

2- Equity Theory:

Adams (1963, 1965) points from different theories in making predictions how individuals manage their relationships with others. The theory states that employees will be motivated if they are treated equitably, and will be demotivated if they are treated inequitably (Armstrong, 2006)

Four propositions hold the objectives of the theory:

1. Individuals evaluate their relationships with others, by comparing the ratios of their outcomes and inputs to the outcomes and inputs ratios of the comparison other.

2. The inequity exists when the outcome / input ratios of an individual and the comparison other are unequal.

3. The greater the individual perceives the inequity, the more distress the individual feel.

4. The greater distress an individual feels, the harder he will work to restore equity. The restoration techniques include, distorting inputs or outcomes, changing the comparison other, or terminating the relationship.

The theory’s distress prediction is based on the hypotheses that individuals are sensitive to equity, so the outcome/ input ratio has to be equal to the comparison other. This premise has been termed “norm of equity”.