Research
Classification
Every entry in the catalog is described by its behavior, in three classes.
The Laboratories classify detections by what they do, not by any theory of what they are. The taxonomy is deliberately behavioral, and deliberately silent on cause.
The three classes
| Class | Behavior | Example |
|---|---|---|
| I -- transient | Strong, structured, does not repeat | The 1979 event |
| II -- persistent | Recurs, holds a stable form | The recovered 1966 tape |
| III -- unresolved | Resists every ordinary explanation | FA-0447; the March coincidences |
A Class I event is the hardest to study, because there is nothing to compare it against and no way to reproduce it. A Class II signal recurs and, in time, most resolve to a known source. A Class III entry is one the Laboratories keep under study, because it is coincident across separated stations, or holds an unexpectedly stable frequency, or recurs on a schedule that matches no known source.
Why behavior, not cause
To classify by presumed cause is to decide the answer before the evidence allows it. The Laboratories have watched the field make that mistake -- a distant quasar once proposed as an artificial signal; radio bursts that mimicked the cosmos and turned out to be a microwave oven. Classifying by behavior is the discipline that keeps the record honest.
- 1.FAL Technical Report 17-002, On the classification of anomalous detections by behavior rather than presumed source.