The Strangeness/Probability Matrix

What follows is subject to continual refinement. When trying to make the seemingly unmeasureable measurable, you often have to iterate. We’re not moving the goal posts, just making them easier to find.

Both strangeness and probability are rated on 0-5 scales.  Where a particular case is placed on each scale can be governed by broad guidelines, but it is ultimately up to the judgment of the investigator.  The thing to keep in mind is the upper right hand corner of the matrix are the cases most deserving thorough investigation. Therefore, I recommend assigning preliminary P/S matrix position and possibly changing it as the investigation proceeds.

Probability describes the extent to which the data in the report is credible.  Strangeness is the degree to which the the report describes behavior, structure and experiences that defy conventional explanation if taken at face value.   Reports can have high strangeness and low probability, high probability and low strangeness, or both.  What follows are my recommended guidelines for each.

Note to our fellow geeks: yes, we are well aware that the usual definition of probability is a number from 0 to 1 inclusive, but human brains don’t work well with small numbers like that. Perhaps at some time in the future, we’ll rescale to a percentage probability (0 to 100 inclusive).


0 – Strong evidence of a hoax or hallucination.  Witness credibility demonstrably low.

1 – Little difference between the report and a fictional story: only a single witness willing to come forth, no physical evidence, no corroboration, no contemporaneous notes, photographs or videos.

2 – Single witness with contemporaneous notes, sketches or sighting reports.  Possibly a second witness, but not a strong corroboration,or considerable collusion on the story before discussion with investigators.  Photographs or videos, if they exist, do not have clear provenance.

3 – Multiple credible witness reports within short time of the sighting with good consistency between witnesses.  Photographs or videos with clear provenance.  Photographs have EXIF data consistent with testimony and have been subjected to careful analysis.  Witnesses do not seek publicity.

4 – All criteria of (3), plus a high degree of independence between highly credible witnesses.    More than 1 video or photograph with clear provenance at the same time.  Physical evidence subjected to analysis.  Thorough investigation conducted shortly after the event.

5 – Both remote sensing (e.g. RADAR, optical) and in-situ physical evidence with clear chains of custody from highly credible sources in addition to the criteria of 4.


0 – With high probability a well-known and understood natural or man-made phenomenon such as a bright planet, Chinese lantern, lenticular cloud, meteor, or aircraft landing lights.

1 – Possibly a known man-made or natural object if one aspect of the report is misreported or misperceived.

2 – More than one significant aspect of the report is highly puzzling.

3 – The report consistently describes behavior and appearance of an object or objects that defies conventional explanation

4 – The report meets the criteria of three, plus indicates interaction with the witness, animals or the environment, such as landing traces, interference with equipment, or communication.

5 – Report meets some of the criteria of 4, plus additional strange aspects such as repetition of events, missing time or time distortion, artifacts, missing time, implants, or other highly strange phenomena.


Comments are closed