Objective personality tests are highly standardized. One of the best known of these tests is the Minnesota Multiphasic Personality Inventory (MMPI) and the subsequent MMPI-2. These standard tests categorize adult personality and psychopathology and can be used for a number of purposes, from screening potential job applicants to determining treatment approaches for mental health disorders.
The benefits of objective personality tests are that they are consistent and quick and cheap to execute. A participant takes the test and a computer or a human proctor can quickly and easily compile and read out the results.
The disadvantage lies in its rigidity. It’s easy for a participant to lie without detection, which will output potentially incorrect results.
On the other hand, projective personality tests present the participant with ambiguous stimuli. The responses to these stimuli are interpreted to reveal hidden emotions and internal conflicts.
The advantages here lie in the subjectivity of the tests, because there are no “correct” answers, which often allows for more honest and insightful responses which in turn work to develop a larger body of work for professionals to gain more insight into human emotion and behavior.
The subjectivity is also a disadvantage, because the proctor plays a role in the ultimate analysis of the responses. A lazy or careless proctor can easily miss insights. These tests are also significantly more expensive and time-consuming to administer and gather results from.