If you’re thinking about using a polygraph, one of the first questions you’ll probably ask is:
“But are the results actually reliable?”
It’s a fair question, and one that deserves a straight answer.
In this article, we’ll break down what polygraph results really mean, how accurate they are, and the most common misunderstandings around lie detector tests in South Africa.
🎯 How Accurate Are Polygraph Tests?
When administered by a trained, accredited examiner, polygraph tests can reach accuracy levels of 85–95%, depending on the case type and method used.
But like any scientific tool, accuracy depends on:
- The examiner’s training and technique
- The type of questions asked
- The testing environment
Polygraphs are not infallible, no test is, but when used properly, they’re an effective method to help detect deception in employment cases, theft investigations, personal disputes, and more.
📉 Factors That Reduce Accuracy
Here’s where polygraph testing can go wrong:
| Risk Factor | Why It Matters |
| Unqualified examiner | Poor training leads to incorrect chart interpretation |
| Improper question structure | Vague or biased questions distort results. |
| Rushed procedures | Skipping the pre-test interview impacts clarity. |
That’s why hiring a certified examiner, like those registered with SAPFED or SAPPA, is essential. These professionals follow ethical protocols that boost reliability and help protect you from legal or reputational issues.
💡 Polygraph Myths vs. Reality
Let’s clear up a few of the biggest misconceptions:
❌ “Polygraphs detect lies directly.”
✔️ False. Polygraphs measure physiological responses (e.g., heart rate and skin response) triggered by emotional reactions, not lies themselves.
❌ “You can beat a polygraph with tricks.”
✔️ Rarely. Most countermeasures either fail or trigger an inconclusive result, which still raises red flags.
❌ “Polygraph results are always admissible in court.”
✔️ In South Africa, polygraph results are typically not admissible as standalone evidence, but can be used as supporting evidence, same as fingerprints.
🧪 What Does The Result of a Polygraph Test Mean in Layman’s Terms?
A professionally conducted polygraph test will usually produce one of three outcomes:
- No Deception Indicated (NDI)/No Significant Reactions (NSR) – No signs of deception detected
- Deception Indicated (DI)/Significant Reactions (SR) – Subject showed physiological signs of lying.
- Inconclusive – Results were unclear or inconsistent.
Examiners don’t make legal conclusions; they provide a professional opinion based on physiological data.
📁 What Happens If the Result Is Inconclusive?
This doesn’t mean someone is lying; it just means their responses didn’t give a clear enough pattern to conclude. This can happen due to:
- Attempted countermeasures
- Poor test conditions
- Translation Issues
A re-test is sometimes offered after rest or clarification.
🧠 So… Can You Trust a Polygraph?
Yes! If you understand what it is and isn’t.
A polygraph test is not a magic truth machine. But it is a structured, scientific process that, when conducted ethically, offers valuable insights into truthfulness, especially in situations where you need clarity fast.
It’s trusted by:
- South African businesses for screening and investigations
- HR departments for internal theft cases
- Private individuals in relationship or dispute situations
- Legal teams for supporting affidavits or investigations
✅ Final Thoughts
Polygraph results are as trustworthy as the examiner administering the test. If you’re working with a certified, experienced professional who uses modern equipment and follows a transparent process, you can trust the results as a serious investigative tool.
But if you’re cutting corners, rushing the process, or ignoring credentials, the outcome might not be worth the paper it’s printed on.
If you want expert, ethical polygraph services backed by decades of experience,
👉 Contact us today for a confidential consultation.