The main reason why someone not trained to administer and interpret an objective personality test is that the examinee may attempt to either "fake good" or "fake bad". This is of course an attempt to make themselves seem nicer or better in some way. It can also be used to make themselves seem as if they have extreme problems. An examinee can attempt to create a "response set", but objective personality tests have "lie" scales built in to identify this when the test is scored.
Another problem can be that people aren't actually lying. They don't understand and we need to be alert for signs of that when assessing our clients. What if the parent can't read well in any language, yet they are ashamed to tell me?
When analyzing the validity of objective personality tests, another issue to look for is comprehension. Many of the parents I work with speak English as a second language There are also many people with English as a first language who cannot read well. They are sometimes uncomfortable telling me that they cannot read the test well enough to answer correctly. When I am concerned that this might be an issue, I often offer to read the test to parents and students. Then I am able to explain questions in different ways and give examples. This is allowed on some personality tests. There are tests in Spanish as well. Many of the parents from small towns in central Mexico can't read in Spanish- they can read in Indian languages such as Nahuatl, an Aztec language.
Several personality tests also have a CD that they can listen to and then respond to questions. I sometimes ask to read the test to students who can't read well. It is harder to come up with a good reason to ask to read a test to a parent without embarrassing them. That's when I just bring out the CD and headphones. Finally, I am sometimes asked to give this test to students who have very low intelligence. They not only can't read the test, but they don't understand any of the questions.
How do we tell the difference between lying and not understanding?
Difference between lying and not understanding
i) Good clinical judgment : observe facial expression, look at clinical history for malingering, ask or consider if faking ...
Why some may be faking bad/good are determined. How to deal with it from a clinical perspective is discussed.