How to Pass The Police Polygraph Test: Ace The Lie Detector Exam

Becoming a police officer isn’t easy. Being a great officer on the force is even harder. Not just anyone can succeed in this challenging career field. Becoming a great officer takes physical and mental abilities and demanding skills.

You have to show your fitness to join the force when you go through the application process. There are lots of hurdles and lots of different tests to pass. Some of the tests look at your physical abilities such as running and push ups. Others examine your physical and mental health. There are also written tests to make sure that you can read and think critically.

Don’t Be Afraid To Take Tests

If you want to work in law enforcement, it helps if you’re not afraid of taking tests. When you go through the application process, you take lots of them. This is not the time for performance anxiety. Sometimes, if you don’t pass an exam, you get a second chance, but this isn’t always the case. Also, many of the tests have specific standards that you have to meet in order to pass the exams. You have to be able to pass the test, even if retries are allowed.

Why Are the Standards So Strict?

Police work is literally life and death. The public trusts you to help them in life-threatening situations. You handle a service weapon. You make decisions about when to arrest people. When a person requests a trial, your testimony is often the most important evidence. These are very serious things, and it’s no wonder that law enforcement agencies want to make sure that you’re particularly qualified before you sign on to work.

The Polygraph Exam

Most likely, you have to undergo a polygraph exam in order to receive the green light to work in law enforcement. This is the case from a rural law enforcement agency all the way to federal agencies like the FBI, the DEA or United States customs. If you don’t get through the polygraph test with flying colors, you’re out of luck. For that reason, it’s worth your while to learn what to expect on the polygraph test. If you know what typical police polygraph questions are, you’re more likely to remain calm on test day.

Aren’t Polygraph Tests Inadmissible?

If you’ve heard that polygraph test results aren’t credible enough to be admissible in court, you’re correct. There are lots of court cases that address why they are not admissible, including Frye v. United States and Daubert v. Merrell Dow Pharmaceuticals. Courts have ruled that these tests aren’t sound enough science for juries to use them to determine whether a person is telling the truth.

Even though polygraph test results don’t come into court on trial day, police departments still use police polygraph questions when deciding who to hire. Even though they might not be sound science, police hiring authorities still think they’re better than taking your word for it. It’s both legal and constitutional for law enforcement agencies to require you to sit for a polygraph exam as a condition of employment. Lots of applicants that might otherwise appear qualified can’t get through the application process because of the results of their polygraph test. Don’t let that happen to you.

How Does a Polygraph Test Work?


A polygraph test takes physical measurements from your body as someone asks you questions. It measures when there are physical changes in your body as you answer questions. These changes are typical when you are lying or trying to mislead the tester. Some of the physical measurements made during testing are blood pressure, pulse and breathing. They can measure breathing either by the chest movements or diaphragm movements.

They attach metal plates to your fingers to see if you’re sweating. They put a cuff on your arm to check your blood pressure, just like when you go to the doctor. Rubber tubes that go around your chest can monitor your breathing. These sensors send data back to a central computer for recording and interpretation.

Are Polygraph Tests Accurate At All?

Some people say that lie detector polygraph tests are accurate between eighty-five and ninety-five percent of the time. Others say there’s no reliability to the tests at all. The test wants to see if these body measurements change when you tell a lie. The theory is that you sweat more and your pulse and blood pressure rise when you lie.

What About the Person Who Gives You The Test?

The person who gives you the polygraph test has likely given many tests. They’re trained to give you the test. They apply their own opinion to the test results to make a conclusion about your truthfulness.

What Questions Do They Ask?

The first thing you do for the test is answer some questions before the formal polygraph even starts. There’s a lot of personal information in these questions. They care about the details, too. They ask you about prior drug use, and they’ll ask you how many times, when and where you used drugs. They’ll also ask you what drugs you did, exactly. They’ll also ask about your criminal history.

If this is making you start to have regrets about your past life, you’re not alone. The polygraph and the police polygraph questions knock out up to a quarter of the applicants from the hiring process. The questions you get in the pre-test are probably similar to the same questions you can expect on the polygraph test itself.

Starter Questions

Once you get hooked up, you get a few starter questions. These can be anything from, “Is it Monday” to “Are you going to tell the truth when you answer questions?” More serious questions to expect later on are “Have you stolen something from a place of employment,” and “Have you given anyone payment for a sexual encounter?”

What Else To Expect

There are short breaks in between questions. They also might ask you a question more than once or even several times. A test can take up to an hour or even longer. It depends on the tester and the standard questions for the department where you want to work.

How To Succeed

If you want to do well on your test, schedule extra time to sleep before your test. Don’t change your routine in the period leading up to the test. Don’t change what you eat or your exercise routine.

Of course, tell the truth on the test. Don’t worry about all the sensors or your nerves. Just listen to the questions and answer them. Listen to the question being asked and respond to it, only. Don’t read anything into the questions. Try to relax and, above all, be honest.