Rio Scale Calculator 
Rev. 1.2, adopted September 2003



Use the boxes below to describe the SETI detection you wish to analyze. Select one option in each of the four boxes. The importance of the event, estimated on a scale of zero (none) to ten (extraordinary), is displayed at the bottom of the page.


Class of
Earth-specific message, or an ET artifact, capable of contact, or a physical encounter
Omnidirectional message with decipherable information, or a functioning ET artifact or space probe
Earth-specific beacon to draw our attention, or an ET artifact with a message to mankind
Omnidirectional beacon designed to draw attention, or an ET artifact with a message of a general character
Leakage radiation, without possible interpretation, or an ET artifact the purpose of which is understandable
Traces of astroengineering, or any indication of technological activity by an extant or extinct civilization at any distance, or an ET artifact, the purpose of which is unknown
Type of
SETI/SETA observation; steady phenomenon verifiable by repeated observation or investigation
Non-SETI/SETA observation; steady phenomenon verifiable by repeated observation or investigation
SETI/SETA observation; transient phenomenon that has been verified but never repeated
Non-SETI/SETA observation; transient phenomenon that is reliable but never repeated
From archival data; a posteriori discovery without possiblity of verification 
Within the solar system
Within a distance which allows communication (at lightspeed) within a human lifetime
Within the Galaxy
of Report:
Absolutely reliable, without any doubt
Very probable, with verification already carried out
Possible, but should be verified before taken seriously
Very uncertain, but worthy of verification efforts
Obviously fake or fraudulent 


Rio Scale Value
and Importance: 0 - None



Webmaster's Disclaimer: This Rio Scale Calculator requires a JavaScript-enabled browser. Your browser must be set to "allow active content." Some browser security settings block active content, and thus will inhibit this calculator's performance.

Although the numerical calculation presented in the "value" box above should be valid across platforms, the graphical "importance" display just below it may be browser-specific. It has been noted, for example, that some versions of Netscape do not print the same results that they display on the screen! In some versions of both Netscape and Microsoft Internet Explorer, clicking the Reload button after computing Rio Scale values yields the correct numerical value, but the wrong graphical "importance" display. If the two are in conflict, the numerical "value" display takes precedence. Your Webmaster regrets the lack of consistant standards in the browser industry.

If your results appear questionable, clear your browser cache and reload this page. Please report any anomalies to the webmaster via email.

The IAA SETI Permanent Committee thanks SETI League member Daniel Boyd Fox for coding the original JavaScript for the Rio Scale Calculator, and Ondrej Koren for porting the site to the current incarnation.