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Polygraph Test Questions, Answered
These are the polygraph test questions we are actually asked, on the phone and in the consultation, written out the way we answer them. How the examination works and what the instrument records. Who cannot be tested on a given day, and why. What a cancellation costs, how far we travel, and when the report lands in your inbox. If your question is not here, phone and ask it.
The short answer
A polygraph is an instrument, not an oracle. It records breathing, blood volume and sweat gland activity continuously while a qualified examiner puts an agreed set of questions. The examiner reads those charts afterwards and gives an opinion. Nothing on the test is a surprise, nobody can be made to sit one, and the result goes to you and to nobody else.
About an hour for each person, most of it spent talking before anything is connected
The report is emailed the same night, or before 08:00 the next morning
Written consent is signed in front of the examiner, every time, without exception
Start here
What a polygraph is, and what it writes down
The word polygraph means many writings, and that is the whole of the idea. It is a scientific instrument that measures several physiological activities at the same moment and records them side by side on one chart, so a reaction can be seen across all of them at once rather than guessed at from one.
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Breathing
Two convoluted rubber tubes, one across the chest and one across the abdomen, record the pattern and depth of respiration through the whole examination.
What it shows The rhythm of breathing, and where it changes
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Blood volume
A cuff, or a similar device, records cardiovascular activity: the relative changes in blood volume that the body makes without being asked.
What it shows Relative change, not a blood pressure reading
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Sweat gland activity
Two small metal plates on the fingers record electro dermal activity, which is the change in sweat. It is the fastest of the three to move.
What it shows Electro dermal activity, second by second
The shape of an appointment
Three phases, in this order, every time
An examination is not one event. It is three, and the first of them is the longest and does most of the work.
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1 The pre-test
Paperwork, then a conversation. The examiner explains the instrument and the procedure, goes through every question that will be asked, and establishes whether the person is suitable to be examined at all, taking their medical and mental history. Consent is signed here.
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2 Chart collection
The instrument is connected and the examiner runs the test, collecting a number of charts rather than one. The questions asked are the questions already discussed. There are no new ones.
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3 Test data analysis
The examiner scores the charts and forms an opinion on the truthfulness of the person examined. Where it is appropriate, that person is given the chance to explain a reaction to one or more questions before the report is written.
Group one
Polygraph test questions about the examination itself9 answers
What the instrument does, what it cannot do, and the things people worry about beforehand that turn out not to matter.
Does a polygraph detect lies?
No, and the distinction is worth having clearly. A polygraph records physiological responses to a series of questions put to a person by a qualified examiner using a validated testing format. It does not read a thought and it never prints the word lie.
What happens afterwards is that the examiner reads the charts and renders a diagnostic opinion as to the truthfulness of the person tested. That opinion is a piece of evidence to weigh with everything else you know about a matter. It is not a verdict, and anybody who sells it to you as one is overselling it.
What happens before the test starts?
The pre-test, and it is the part of the appointment that decides whether the rest of it is worth anything. The examiner completes the required paperwork and talks to the person about the test: what the instrument is, how it is attached, what the procedure will feel like.
Every question that will be asked during the examination is discussed in that conversation first. Nothing on the test is a surprise, which is deliberate; a surprise question produces a reaction to the surprise. The examiner also establishes whether the person is suitable to undergo an examination at all, which means taking a medical and mental history.
How accurate is a polygraph examination?
The American Polygraph Association puts it at 85% to 98%, and there are studies on record suggesting the polygraph does better than that. A range rather than a single number is the honest answer, because accuracy moves with the testing format, with the quality of the pre-test, and with whether the person was fit to be examined on the day.
It is also the reason an examination belongs inside an investigation rather than instead of one. Used that way it is very often the fastest route to the truth available to you, and the cheapest.
What instrument do you use?
A computerised instrument from the current LX series, with tracings running for respiration, cardiovascular activity and electro dermal activity, and further channels alongside them: a PPG channel, and a sensor in the seat that records movement. Those tracings are what the examiner reads once the relevant questions have been put.
The models we run and how often they are calibrated are set out on the polygraph services page, along with who does the calibrating.
Can nervousness change the result?
No. The technique allows for a person's general nervous tension, and most people are nervous before and during an examination. That nervousness changes the level the recordings are made from. It does not change what the recordings say.
Put plainly: being nervous is not a finding, it has never been a finding, and no examiner has ever written a report on the strength of it.
Does medication affect the results?
No. There is no medicine that has an influence on the outcome of the test results. Chronic medication is not a reason to move an appointment and it is not something anybody needs to stop taking beforehand.
Being rested and reasonably healthy on the day is a different question, and it does matter. It is answered under booking, below.
Can a pregnant woman be examined?
Yes, with her consent, and preferably not beyond six months. We have done it before. Tell the office when you book so the examiner can plan the appointment around it rather than find out on the morning.
Can somebody be forced to take a polygraph examination?
No, unless it is stipulated in a contract they have signed. Beyond that, nobody can be made to undergo an examination, and consent has to be real rather than assumed: the person must be properly consulted and informed about the intended examination, not simply told or instructed to attend, and they sign a written consent in front of the examiner on the day.
That requirement protects you as much as it protects them. An examination taken under duress is worth nothing to anybody afterwards, least of all at a hearing.
It is also worth remembering what the examination is most often used for. It is the quickest and most effective way of taking an innocent person out of an investigation and letting them get back to work.
How confidential is an examination?
Every conscious effort is made to keep the privacy of the person examined and the client's information intact. Files are restricted to those immediately involved in the procedure. Results are disclosed only to the people entitled to the facts of them, and to anyone else the due process of law requires.
In practice that means the examiner does not discuss a case with a colleague of the person examined, results are not read out to a room, and nothing is published anywhere.
Group two
Booking an examination6 answers
When we can be there, what has to happen first, and the things worth checking the day before rather than on the morning.
How far ahead do I need to book?
Usually not far at all. There is often a slot open on the day, and the next day is normal. As a working rule we can put an examination in the diary within two or three working days of being asked for one, and there is more than one examiner, so a full diary for one of us is not a full diary.
We prefer to work by appointment because we are busy, but urgent is a real category and we treat it as one. If it is urgent, phone rather than email.
What time of day can the examination start?
We work to your day. If you need an examiner on site at 06:00, we will be there.
Left to ourselves we prefer to start at 09:00 and finish by 17:00, and that preference is about the traffic and the crime rate on either end of the day rather than about the diary. Say what you need and we will work to it.
Do you work Saturdays, Sundays and public holidays?
Saturdays, between 08:00 and 12:00. Not Sundays. Public holidays are arranged beforehand rather than booked on the day, so give us notice and we will make a plan.
The office itself never really closes, in the sense that somebody will answer you outside those hours. That is not the same thing as an examination being available, and it is worth not confusing the two when you are working to a deadline.
What is the order of things, from the first phone call to the appointment?
Quote, then payment, then booking. The order is not a preference: the booking system deletes an appointment made before the payment has come through, so a slot taken out of sequence does not hold.
- Get the quote. Fill in the quote form and it comes back to you by email as a formal quote. Check the spam folder if it has not arrived.
- Pay, using the quote number. It is printed on the top right of the quote, and the banking details are in the middle of the same page. That number is the reference.
- Book the slot. Once the payment is made, book the appointment and email the proof of payment through, or phone the office and we will do it with you.
- The invoice follows. Once a quote is paid the office sends the invoice, showing the deposit and the balance as lines on one document.
The three ways to pay, and what each one costs, are set out on the pricing page.
What if the person does not speak English or Afrikaans?
Then they have a right to an interpreter, and we need to know before the day rather than on it. The interpreter has to be an independent person, trained and experienced in the complexities of interpreting a polygraph examination, and approved by the examiner. A colleague who happens to speak the language is not an interpreter for this purpose.
There is also an examiner in the practice who is fluent in five official African languages, which often removes the problem rather than solving it. Ask for that when you book and we will put the appointment with him.
Who cannot be examined on the day?
The person to be examined has to be reasonably well rested and reasonably healthy. We cannot examine somebody who:
- has just come off a full night shift, or has not slept properly in the days before
- is emotionally upset or in distress
- is ill, injured, or in pain
- smells of alcohol
None of that is a judgement about the person. It is that a body in one of those states does not produce charts anybody can read fairly, and the fair thing to do is move the appointment. Check it the day before. An appointment abandoned on the morning is still charged for.
Group three
The day, and the report4 answers
How long it takes, how many people fit into a day, and when the written result reaches you.
How long does an examination take?
Normally an hour per person. It moves with how much there is to talk about: a matter with a lot of background takes longer in the pre-test, and the pre-test is where most of that hour goes.
Add to that the consultation with you at the start of the day, and ten to fifteen minutes for the examiner to set the instruments up. Those two happen once, not once for each person.
How many people can be examined in one day?
One examiner does five to seven in a day. Seven is achievable when we are at one site with everybody available and the case facts are the same for each person, so nothing has to be re-consulted between them.
If you have more people than that, we send more than one examiner rather than rushing anybody through. The point of the examination is accurate information, and there is no version of hurrying it that produces more of that. The quote works the number of examiners out for you and prices it.
When do the results come back?
The report is emailed the same night, or before 08:00 the following morning. That is the standard, not the best case.
If you are running a CCMA matter or a disciplinary with a date already set on it, say so when you book. Those are the ones we treat as immediate, and knowing about it in advance is what makes that possible.
Is the report released before the balance is paid?
No. Where a deposit was paid rather than the full amount, the report is released once the balance is settled.
It is worth knowing that before the day rather than after it, particularly if somebody is sitting waiting on the result to run a hearing. Paying in full before the examination starts avoids the step entirely, and takes ten percent off the whole engagement while it is at it.
Group four
Fees, quotes and cancellations7 answers
What each line on a quote is for, and the two rules that surprise people most: travel and cancellation.
Why is there a consultation fee?
Because the consultation is the work. On the day of the booking the examiner sits down with you before anything is connected to anybody, and all the relevant case facts are discussed. Every case is different from the last one, and the questions put on the test are built out of that conversation.
It is not a formality and it is not five minutes. It can run from half an hour to a full hour depending on the matter. A test with a rushed consultation behind it is not worth running, which is why it is a line on the quote rather than something quietly skipped.
Why do infidelity and sexual harassment cases cost more?
Because they are not run to the usual protocol. Every one of them is unique and has to be dealt with differently: the consulting takes considerably longer than a normal case, and all the relevant questions have to be properly discussed and formulated before the test starts.
Those matters are quoted off their own published prices rather than the per person table, and you can see both on the pricing page.
Do you refund a cancelled appointment?
No. When you book an examiner you are booking the time, one hour for each person to be examined, and once a booking is cancelled that time is gone. Five bookings is five hours held for you, and five hours that could have gone to another client and now cannot.
We do understand business and we are reasonable about it. Where it has been arranged with the office beforehand and agreed between both sides, a credit note is issued instead. That is the exception rather than the rule, and it depends entirely on being told early.
What happens if I postpone?
The appointment moves, and a further travelling fee goes onto the invoice, because the trip that was already planned and priced still has to be made a second time.
Give as much notice as you can and there is usually a way to keep that down, particularly if we are due in the same area anyway.
How is travel charged?
Per kilometre, per examiner, per trip, worked out on the real road distance between the office in Centurion and where you are. Two examiners at the same site on the same day is two travel charges rather than one, because it is two vehicles.
There is a fixed travel rate inside the immediate Johannesburg and Pretoria range, which exists so that a local quote is simple to read with nothing hidden in it. Beyond that the quote measures the distance itself and shows it on its own line, so the number on the page is the number on the invoice. The rates are on the pricing page.
Is the ten percent discount automatic?
Yes, if you take the route that carries it. Choose to pay in full before the examination starts and the quote comes out at the special price with the discount already worked into every line of it.
There is no code to type and no second quote to ask for. The quote form applies it and emails you one document.
How long is a quote valid for?
Fourteen days. Long enough to take it to whoever signs it off and have it still be the price when it comes back.
A quote also goes to the office at the same time it goes to you, so if you phone about it we already have it in front of us and you will not be asked to read the number out.
Group five
Where we work4 answers
This practice is mobile by design. The office exists, and most examinations do not happen in it.
Do you come to us, or do we come to you?
Both, and it is your choice. We come to your premises or to a private residence, which is what most clients want, because it means nobody has to be released from a shift to travel.
There is also an examination room at the office in Centurion, and for a personal matter it is very often the better of the two: neutral ground, nobody walking past, and nothing about the appointment visible to anybody else.
What is the mobile examination vehicle?
A solar powered vehicle fitted out as an examination room. It is driven to your place and the examinations are conducted inside it.
It exists for sites with nowhere suitable to work: no quiet room, no door that closes properly, or nowhere private enough for the person being examined to be comfortable. The procedure asks for a closed office space with the door shut and no disturbance, and where a site cannot offer that, the vehicle brings one with it. It is quoted as its own item rather than assumed.
How far do you travel?
Across Gauteng as a matter of routine, and regularly out to Krugersdorp, Vereniging and Nelspruit.
- Around the country. There are members of the practice working in Polokwane, Cape Town, Durban, Johannesburg and Gqeberha
- Across the border. Work has been done in Mozambique, Eswatini, Zambia and Mauritius
If you are somewhere not on that list, ask rather than assume. The answer is usually yes, and the quote will price the distance honestly either way.
Where is the office?
45 Bernardie Street, The Reeds, Centurion, 0061, in Gauteng. There is an examination room there and it runs by appointment; there is no walk in counter, and turning up unannounced means finding the door shut and an examiner somewhere on the road.
Directions, a map and the ways to reach us are on the contact page.
Group six
The other things we do4 answers
A polygraph is one of four services here, and the other three are what people ask about second.
Do you attend CCMA matters?
Yes. Where an examination forms part of a labour matter, the examiner attends the CCMA on the client's behalf, either in person or by video call, whichever suits the case and the diary.
That attendance is charged by the hour and quoted separately from the examination itself, because it is a separate day's work. What the labour side of the practice does more broadly is on the labour assistance page.
Do you run criminal background checks?
Yes, and there is no appointment and no examiner involved in one. You email us a full name and an identity number, or a passport number where the person is not a South African citizen, it goes to the record centre for processing, and the result comes back to you in writing.
The written consent of the person being checked is required first. What a check covers, what it does not cover, and how long the processing takes are all on the criminal background checks page.
Do you take on investigations?
Yes. Fraud, theft, infidelity, and complex matters that need a specialist brief, handled by a dedicated investigation team rather than by the examiners.
There is no rate card for it and there is no online quote, and that is deliberate rather than evasive: no two of those matters cost the same and a form would give you a wrong number. Phone the office and the team leader will go through the case facts with you and quote on what is actually there. More on the investigations page.
Do you help employers with labour matters?
Yes. There is a labour department inside the practice and it works on the employer side, which the client should know before phoning: the service is built around keeping a matter from reaching the CCMA or a bargaining council unnecessarily, and around having the paperwork in order before it has to stand up anywhere.
All four services, and how they fit together, are set out on the services page.
Seven things to settle first
Before you make the booking
Almost every appointment that goes wrong goes wrong for one of seven reasons, and all seven are settled beforehand in a phone call. Work down this list before you take a slot and the day itself is straightforward.
Consent, properly obtained
The person must be consulted and informed about the intended examination, not simply told to attend, and must be completely willing to sign a written consent for the examiner. If somebody arrives having been deceived about why, or refuses on the day, the session is terminated and the appointment is still paid for in full.
An interpreter, if one is needed
Decide beforehand and tell us. Anybody not completely fluent in English or Afrikaans has the right to one, and that interpreter must be independent, trained in the complexities of polygraph interpretation, and approved by the examiner.
Fitness on the day
Reasonably well rested and reasonably healthy. Not straight off a night shift, not ill, injured or in pain, not distressed, and not smelling of alcohol. Check it the day before rather than discovering it in the room.
The quote and the terms in hand
Get the quotation and a copy of the terms and conditions of service before you commit, so the cost implications and the requirements are known rather than assumed. Nobody should be reading a term for the first time after an appointment has gone wrong.
Payment, then the slot
Pay against the quote number, then book. An appointment booked before payment is deleted automatically by the booking system, so doing it in the other order costs you the slot you were trying to protect.
The case facts
Have the background ready for the consultation. On a theft, that means the approximate date, the place or address, what was taken and what it was worth. The questions on the test are built from those facts, so thin facts make a thin test.
Language support, if you want it
There is an examiner in the practice fluent in five official African languages. Ask for that at the time of booking rather than afterwards, so the appointment is put with him from the start.
Still not answered
Ask the examiner directly
If the thing you need to know is not on this page, it is because nobody has asked it yet. Phone and ask, and the answer goes onto this page for the next person. There is no charge for a question and nothing is booked by asking one.
Group six
The other things we do4 answers
A polygraph is one of four services here, and the other three are what people ask about second.
Do you attend CCMA matters?
Yes. Where an examination forms part of a labour matter, the examiner attends the CCMA on the client's behalf, either in person or by video call, whichever suits the case and the diary.
That attendance is charged by the hour and quoted separately from the examination itself, because it is a separate day's work. What the labour side of the practice does more broadly is on the labour assistance page.
Do you run criminal background checks?
Yes, and there is no appointment and no examiner involved in one. You email us a full name and an identity number, or a passport number where the person is not a South African citizen, it goes to the record centre for processing, and the result comes back to you in writing.
The written consent of the person being checked is required first. What a check covers, what it does not cover, and how long the processing takes are all on the criminal background checks page.
Do you take on investigations?
Yes. Fraud, theft, infidelity, and complex matters that need a specialist brief, handled by a dedicated investigation team rather than by the examiners.
There is no rate card for it and there is no online quote, and that is deliberate rather than evasive: no two of those matters cost the same and a form would give you a wrong number. Phone the office and the team leader will go through the case facts with you and quote on what is actually there. More on the investigations page.
Do you help employers with labour matters?
Yes. There is a labour department inside the practice and it works on the employer side, which the client should know before phoning: the service is built around keeping a matter from reaching the CCMA or a bargaining council unnecessarily, and around having the paperwork in order before it has to stand up anywhere.
All four services, and how they fit together, are set out on the services page.