Rio 2.0: revising the Rio scale for SETI detections
Almár and Tarter (2000) attempted to encapsulate the significance of a possible SETI signal using a simple linear scale. This was named the Rio scale, as it was first presented at the 51st International Astronautical Congress in Rio de Janeiro (see also Almár 2001, 2011; Almár and Tarter 2011). Broadly, this tool was designed for communicating with the public as to ‘how excited’ they should be regarding a signal. The scale is constructed by multiplying two numbers: Q, which describes the consequences of a signal if it is an ETI discovery, and δ, a description of the credibility of the signal being truly ETI. The resulting scale
R = Qδ (1)
ranges between 0 and 10, with 10 being of the greatest possible excitement.
International Journal of Astrobiology, Cambridge University Press.