The terms "job satisfaction" and "motivation" are often used interchangeably. However, this is incorrect. Job satisfaction refers to the pleasure or reassurance that a job provides a person. A person who is satisfied with his job is said to have high job satisfaction. By contrast, motivation refers only to the reasons a person performs a job, regardless of whether the job brings him pleasure. However, the terms are closely related.
Motivation refers to the reasons -- the motive -- that a person performs a particular job. A person's motives for doing a particular job can vary widely. While some do a job because it makes them happy, others do it simply because they are paid to do it and without a regular salary they would end up homeless and hungry. A person's motives for performing the work he does are not always knowable.
Job satisfaction refers to the satisfaction that a person receives from performing his job. The satisfaction can take many forms -- satisfaction at the work that he has accomplished, satisfaction at the effort he puts into the job, satisfaction at the help he has provided others -- but all involve some degree of psychological contentment. Job satisfaction can often be difficult to measure, because people define satisfaction in different ways.
Motivation and satisfaction are closely related, in that job satisfaction can be described as a type of motivation. However, a person's satisfaction with his job and his motivation to perform the job can exist independently of each other. For example, a person can be satisfied by his job but his motivation for doing the job can exist independently of his satisfaction. He might do the job for money, with his satisfaction merely incidental.
Sometimes, a person is not aware of either his motivation for doing the job or the satisfaction it brings. Like most psychological conditions, motivation can remain elusive and unknowable. In addition, satisfaction can be difficult to measure, because the term is relative. However, many managers believe that employees are better motivated by the prospect of job satisfaction than they are by other types of motivation, whether this job satisfaction is achieved or not.