There are several types of objective personality tests. The most popular and most widely used in the world is known as the Minnesota Multiphasic Personality Inventory, second edition (MMPI-2). Objective personality tests offer mental health professionals a way to better understand their clients and possibly look into any mental illness or disorder.
A disadvantage of objective personality tests can be the sheer length. Unlike tests that give a simple insight into someone's personality, an objective personality test such as the MMPI-2 is used to determine predictions and outcomes of treatments for patients. The MMPI-2 has 567 items, making it the longest commonly used personality inventory.
Cost and Time
An advantage of objective personality tests is that they are relatively cost effective. They only use paper and can be scored by hand or using a machine. OPTs can also be completed on the patient's schedule; this contrasts with projective tests, which must be administered by a professional through use of equipment. OPTs can be taken home with the client and returned later.
Objective personality tests are, obviously, objective. Questions and answers are usually in a true-or-false format. This makes scoring and evaluating the data simple and removes possible bias of the scorer. Although this is a great advantage, scorers must be vigilant in correct scoring procedures as incorrect scoring can lead to misdiagnoses.
With objective personality tests, there is always the possibility that the test taker is not telling the complete truth. The MMPI-2 has gone to great lengths to check for lies using a validity scale, but others, such as the Myers-Briggs Personality Inventory, can be subject to untruths.