The Rio Scale of Extraterrestrial Contacts

IAA SETI Permanent Committee: Rio Scale (Iván Almár and Jill Tarter, in the 51st International Astronautical Congress, 29th Review Meeting on the Search for Extraterrestrial Intelligence, in Rio de Janeiro, Brazil, in October, 2000) is a scale for assessing putative contacts with extraterrestrial intelligent entities. It was devised in analogy with several other such scales, and the higher a putative contact scores, the greater is its importance. It uses this scale: Its value is calculated in this fashion:
(quality) * (reliability)
where
(quality) = (type) + (method) + (distance)
Type: Method: Distance: Credibility or Reliability: From IAA SETI Permanent Committee: Rio Scale Calculator with a few changes in wording.

Notes: The motivation for the scale is explained in Almár and Tarter 2000 The Discovery of ETI as a High-Consequence, Low-Probability Event and Almár 2001 How the Rio Scale Should Be Improved. It is applied to several science-fictional scenarios in Shostak and Almár 2002 The Rio Scale Applied to Fictional "SETI Detections", and the examples there should give an idea of how to use this scale.

Here are some similar sorts of scales:


Here are some science-fiction scenarios and also some nonfiction ones, taken from the papers "The Rio Scale Applied to Fictional 'SETI Detections'" (Contact, 2001: A Space Odyssey, Stargate, the Mars Face, and the EQ Pegasi hoax) and "How the Rio Scale Should Be Improved" (the WOW signal), as illustrations of how to use it. I have added to the ones for 2001 and Stargate, and I have also added ones for Mars's canals, pulsars, KIC8462852 ("Tabby's Star"), and the recently detected one from star HD 164595's direction.

Event Obs Type Method Distance Reliability Rio Value
Contact (movie, Carl Sagan, 1997)
Immediately following detection 3 - 6 5 1 - 4 3 4 - 8
After confirmation by other telescopes 3 - 6 5 1 - 4 4 6 - 10
After transponded TV broadcast discovered 6 5 3 4 9
Independence Day (movie, 1996)
Immediately following detection 3 - 6 5 1 - 4 3 4 - 8
Moments later, after confirmation 6 5 4 4 10
2001: A Space Odyssey (movie, 1968)
Discovery 1 4 4 4 6
Activation (added by myself) 5 4 4 4 9
Stargate (movie, 1994)
Following 1928 discovery 1 4 4 1 2
Seven decades later, constellations recognized (me: distance from 1 to 4) 1 4 4 4 6
When it is activated (added by myself) 5 4 4 4 9
The Mars Face (1976)
Following 1976 discovery in Viking orbiter data 1 4 4 1 2
After 2001 Mars Global Surveyor high-resolution imagery 1 4 4 0 0
EQ Pegasi hoax (1998)
After SETI League notification, lack of confirmation by League members 2 - 6 3 2 1 1 - 2
After BBC story, claims of other amateur confirmations 2 - 6 5 2 2 3 - 4
After Australian and US observations, additional website anomalies 2 - 6 3 2 0 0
The WOW signal (1977)
Ohio State University observation (me: obs type fixed) 3 - 4 3 1 - 3 1 1 - 2
The HD 164595 Signal (2015): score equal to the WOW signal's score
Mars's Canals (1877, my scoring)
Around 1900 (consensus) 1 4 4 2 3
Percival Lowell 5 4 4 4 9
Around 1950 (consensus) 1 4 4 1 2
After Mariner 9 1 4 4 0 0
Pulsars (1967, my scoring)
Discovery 2 - 4 4 1 - 3 1 1 - 2
Identification as Neutron Stars 2 - 4 4 2 0 0
Star KIC8462852 ("Tabby's Star", 2015, my scoring)
Kepler satellite observations 1 4 2 1 1

Here is a comparison of claims of extraterrestrial activity in our Solar System. These claims range from claims in the mainstream scientific literature to claims made by paranormalists, but it is nevertheless worthwhile to compare them. The reliability is rather subjective, so I'll use the full range of nonzero values.

Event Obs Type Method Distance Reliability Rio Value
Mars's canals 1 4 4 1 - 4 2 - 6
Mars's moon Phobos's hollowness 1 4 4 1 - 4 2 - 6
The Mars Face 1 4 4 1 - 4 2 - 6
The Tunguska explosion 5 1 - 2 4 1 - 4 2 - 7
AA reports: artifacts, uninterpretable 1 1 4 1 - 4 1 - 4
AA reports: artifacts, interpretable 2 1 4 1 - 4 1 - 5
AA reports: artifacts, message 4 1 4 1 - 4 2 - 6
AA reports: contacts 6 1 4 1 - 4 2 - 7
AA archeology: artifacts, uninterpretable 1 4 4 1 - 4 2 - 6
AA archeology: artifacts, interpretable 2 4 4 1 - 4 2 - 7
AA archeology: artifacts, message 4 4 4 1 - 4 2 - 8
UFO observations 5 4 4 1 - 4 2 - 9
UFO contacts 6 4 4 1 - 4 2 - 9

AA = ancient aliens or ancient astronauts. Evidence of them may either be reported on or else discovered archeologically. If reported on, then we would work from documents that contain those reports.

Contacts include both abductions and friendly contacts, and the latter sort would clearly be the most informative -- if there is any reason to believe that they are anything more than pure fantasy (reliability 0).


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