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Results Guide • Timing • Report Explained

P300 EEG Results: Timing, Delivery and What Your Report Contains

You've had the test. Now what? When do results come? How are they delivered? What does every section of the written report actually mean? This guide covers everything from the moment the headset comes off to the moment the report lands in your inbox.

SW

Dr. Sarah Williams

Lead P300 EEG Researcher — DeceptionDetection.co.uk

Dr. Williams delivers results for our private and relationship testing cases and handles most post-test consultations. She wrote this guide based on the questions clients consistently ask most as they wait for their reports — because the period between "test done" and "report received" is often the hardest.

The Results Timeline

The test ends when the stimulus sequence completes and the headset is removed. From that point, here is exactly what happens and when.

Now
Test ends — headset removed
+20–30 min
Data processing complete
Same day
Verbal result delivered
Within 24 hrs
Full written report by secure email
On request
Expert witness statement (legal use)

The processing window — what is happening in those 20–30 minutes

The 20 to 30 minutes between the test ending and results being communicated is not administrative delay — it is the core analysis. Your examiner is working through the following steps with your raw EEG data:

  • Epoching: The continuous EEG recording is segmented into time windows around each stimulus — typically −200ms to +800ms relative to stimulus onset.
  • Artefact rejection: Epochs contaminated by eye blinks, movement or muscle activity are identified and excluded. Only clean epochs proceed to analysis.
  • Averaging: Epochs are averaged separately for probe stimuli and neutral fillers. This amplifies the consistent P300 signal while cancelling random neural noise.
  • Amplitude measurement: Peak P300 amplitude and latency are measured for each stimulus category across the key recording channels — particularly the parietal sites where the P300 is largest.
  • Statistical calculation: The deception probability score is calculated from the amplitude difference between probe and filler categories, using our validated statistical model.
  • Examiner review: The output is reviewed by the examiner before any result is communicated. Anomalous patterns — unusual latency, insufficient clean epochs, borderline scores — are flagged and assessed.

You are not waiting for paperwork to be filed. You are waiting for science to be done carefully.

If the processing takes longer than expected — because the examiner has flagged something worth investigating in the signal — that is a good sign, not a bad one. It means the analysis is being taken seriously rather than rushed to a conclusion.

The Verbal Result — What You Hear at the Appointment

Once the analysis is complete, the result is communicated verbally by your examiner at the appointment. It is delivered clearly and directly — in plain language, without jargon or hedging.

Clear Result
No Deception Indicated
<30%
No meaningful P300 recognition response was detected on probe stimuli. The subject's brain did not recognise the specific probe information tested.
⚠️
Deception Indicated
Deception Indicated
>70%
A significant P300 recognition response was detected on probe stimuli. The subject's brain showed neural recognition of the probe information.
⏸️
Inconclusive
Inconclusive
30–70%
Data quality or statistical confidence was insufficient for a definitive conclusion. A free retest is offered. See our accuracy guide for why this happens.

The deception probability score — what it means

The deception probability score is the statistical output at the heart of the result. Here is how to read it.

0% — No recognition Borderline zone 100% — Strong recognition
Clear (<30%)
Inconclusive (30–70%)
Deception indicated (>70%)

A score of 6% means the probability of deception is very low — the probe and filler P300 amplitudes were statistically indistinguishable, indicating no stored recognition of the probe stimuli. A score of 94% means the probability is very high — the probe amplitude was substantially elevated above filler, indicating clear neural recognition.

The borderline zone — approximately 30% to 70% — is where we issue inconclusive results rather than forcing a definitive conclusion on borderline data. A score of 52% is not a "probably guilty" finding. It is an honest statement that the data did not clearly discriminate between the two categories.

The confidence interval

Every deception probability score comes with a confidence interval — a statistical range that reflects how precisely the score is estimated from the available data. A score of 87% ± 4% is more precise and more reliable than a score of 72% ± 18%. The confidence interval appears in the written report and forms part of how we determine whether a definitive result is appropriate.

Taking time with the result

Whatever the outcome, you are not expected to respond immediately. Your examiner will give you time to sit with the result, ask questions, and repeat anything that needs clarifying. There is no rush to leave the room, and no pressure to make any decisions while you are still at the appointment. The full written report arrives within 24 hours — giving you the chance to absorb and review everything more carefully in your own time.

The Written Report — Section by Section

The full written P300 EEG report arrives by secure email within 24 hours of your appointment. Here is every section it contains, what it shows and why it is included.

Section 1

Cover & Case Reference

Date, time and location of the test. Subject reference number (names are not used in the report body for privacy). Examiner name and credentials. Report version and issue date.

Why it matters: Establishes the chain of custody and links the report to the specific test session for legal or HR use.
Section 2

Executive Summary

The overall result in plain language — clear, deception-indicated or inconclusive — with a brief paragraph explaining what the finding means in context. This is the section most clients read first.

Why it matters: Gives an immediately accessible result for personal use and for non-technical recipients in HR or legal contexts.
Section 3

Deception Probability Score

The numerical score with confidence interval. The decision threshold used (typically 70% for deception-indicated, 30% for clear). The statistical model applied.

Why it matters: Quantifies the finding and allows expert reviewers to assess whether the threshold applied was appropriate.
Section 4

Stimulus Design Record

A record of the probe stimuli used and the neutral filler categories. This does not reproduce the specific probe content (which remains confidential) but documents the structure of the test design.

Why it matters: Allows assessment of whether the stimulus design was appropriately specific to the matter under investigation.
Section 5

Raw EEG Waveform Data

The averaged EEG waveforms for probe and filler stimulus categories across all 8 recording channels — graphed as time-amplitude plots. This is the core neurological evidence behind the finding.

Why it matters: Allows independent expert review and verification of the P300 amplitude difference that drove the result.
Section 6

P300 Amplitude & Latency Table

Numerical amplitude values (in microvolts) and peak latency (in milliseconds) for both probe and filler conditions, channel by channel. The amplitude difference — the key measurement — is highlighted.

Why it matters: Provides auditable numerical data for any expert who wishes to independently verify the statistical calculations.
Section 7

Artefact Rejection Log

The number of epochs collected, the number rejected due to artefacts, the reason for rejection (blink, movement, poor signal), and the number of clean epochs that contributed to the analysis.

Why it matters: Demonstrates data quality and allows assessment of whether sufficient clean data underpins the result.
Section 8

Examiner's Professional Conclusion

The examiner's signed professional conclusion — interpreting the statistical findings in the context of the specific case. Includes the examiner's name, qualifications and professional registration details.

Why it matters: Provides the professional accountability and credentialling required for legal and HR submission.

How to Use Your Report

The report is designed to be usable across a range of contexts. Here is how different clients typically use it.

💑

Personal & Relationship Use

Most clients in relationship situations use the executive summary and probability score for personal conversations. The full technical report is available if needed — but many clients find the clear verbal result is what they needed most.

🏢

HR Disciplinary Proceedings

The full report — particularly the executive summary, probability score and examiner conclusion — can be submitted to HR investigations and disciplinary panels alongside other evidence. HR teams do not need to interpret the EEG data directly.

⚖️

Employment Tribunals & Civil Proceedings

The complete report, including raw EEG waveforms and the artefact rejection log, is formatted for submission to legal proceedings. Our examiners can provide expert witness statements if results are challenged. See our legal admissibility guide.

🛡️

Insurance & Fraud Investigation

Reports for insurance fraud cases include all technical documentation formatted for IFB referral and civil claim dispute. Our corporate investigation team handles these from the start to ensure the report is structured appropriately.

Sharing the report

The report is yours — you decide who sees it. We will not share it with any third party without your explicit written consent. If you need to submit it to a solicitor, HR manager or insurance provider, you can forward it directly. If you need a copy provided under legal instruction — for example, if it is required as disclosure in proceedings — we can provide it through the appropriate channels on request.

Report retention

We retain a secure copy of your report and the underlying EEG data for 12 months from the date of the test, in line with our data retention policy. During this period, if the report needs to be reissued, supplemented with an expert witness statement, or reviewed in the context of subsequent legal proceedings, we can access the original data. After 12 months, the data is securely deleted unless you have requested an extended retention period in writing.

If Your Result Is Inconclusive

An inconclusive result is not a failure — it is an honest acknowledgement that the data quality or statistical confidence was insufficient to support a definitive conclusion. Here is what happens next.

  • Immediate explanation: Your examiner will explain precisely why the result is inconclusive — whether it was signal quality, insufficient clean epochs, a borderline probability score, or something else. You will not be left without an explanation.
  • Free retest offered: All inconclusive results trigger an automatic offer of a free retest. The retest is at no additional cost when the inconclusive result was caused by factors on our side — equipment, environment or signal quality.
  • Modified approach where appropriate: If the inconclusive result was influenced by subject-related factors — excessive movement, sustained inattention — we will discuss whether a different timing, location or preparation approach would improve the data quality on retest.
  • Improved stimulus design if needed: If the inconclusive result reflects a stimulus design issue — probes that were insufficiently specific — the retest is designed around better-targeted information from an extended pre-test consultation.
  • No forced conclusion: We do not issue a clear or deception-indicated result based on borderline data. An inconclusive report is issued rather than a forced conclusion — and that inconclusive report is a valid, documented outcome, not a blank.

Our accuracy data shows that 91% of retested inconclusive cases return a definitive result on retest. The rate of subsequent incorrect results following a retest is not meaningfully higher than for first-time tests — the retest protocol is the same, and the quality assurance framework applies equally.

Ready to Get Your Answer?

Verbal result the same day. Full written report within 24 hours. P300 EEG tests from £499 across the UK.

Frequently Asked Questions

You receive a verbal result on the same day as your appointment — typically 20–30 minutes after the test ends while data processing is completed. The full written report is delivered by secure email within 24 hours. For urgent HR or legal situations, same-day written report delivery can be arranged — please mention this when booking.
A score of 87% means the statistical analysis found an 87% probability that the subject has stored neural recognition of the probe stimuli — based on the P300 amplitude difference between probe and filler categories. Scores above 70% are reported as deception-indicated. Scores below 30% are reported as clear. The score is not a percentage of certainty about guilt — it is a measure of the strength of the neural recognition response detected.
Yes — the report is yours to share as you choose. It is formatted specifically for submission to HR processes, employment tribunals, civil proceedings and insurance dispute contexts. If your solicitor or HR manager needs to speak with our examiner about the report content, expert witness statements can be arranged. See our UK legal admissibility guide for detail on using P300 evidence in legal proceedings.
Both. The executive summary gives the result in plain language for immediate use. The full report also includes the raw EEG waveform charts for all 8 channels, numerical P300 amplitude and latency measurements per stimulus category, the artefact rejection log, and the examiner's signed professional conclusion. This makes the report fully auditable — any independent expert can review the underlying data rather than simply trusting the conclusion.
Your examiner will explain the specific reason for the inconclusive result at the appointment. A free retest is offered in all inconclusive cases. 91% of retested cases return a definitive result. We never force a definitive conclusion from borderline data — an inconclusive result is a valid documented outcome, not a blank, and the report we issue explains what the data showed and why it did not meet our minimum threshold for a definitive conclusion.
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