I respectfully disagree. Any investigator "worth his salt" should be able to conduct a better interview, even if he had to use questions similar to the ones on the Civil Service test, then just answering, Agree, Strongly Agree, etc, on a written test. That's what detectives / investigators do, they interview people and get to know whether they're lying, telling the truth, being sincere, etc. Almost anyone can sit in a room with no one watching them and answer questions on a piece of paper and be able to "beat the system" as others on here have said. Sure, they could do the same with a background investigator but at least the investigator has a better chance than a piece of paper.A background investigator wouldn't necessarily uncover as much as a comprehensive personality assesment would. These tests are very specific and measure traits like cynicism, antisocial behavior, demoralization, Etc. I guess it makes the test a more rounded judge of a candidate as opposed to back when they were more like straight IQ tests. Plus this gives an edge to a candidate that has a great disposition for law enforcement, but might not test as well as others.
Just my opinion after taking two Civil Service tests, being an investigator, and listening to what many others have said in this thread. I hope those that deserve to be hired, are.