The PSI Scale

The Psionic Standard Identification Scale, or PSI Scale, is the standardized method of measuring psionic ability. The PSI Scale is often used as a general average for an entire species, and is also used for individuals who may differ from the norm. Psionic potential is measured from 0-15, with each level increasing almost exponentially in power over the previous.

At the highest level, 15, individuals achieve a so-called "Ascension" - a state of being in which one becomes pure psionic energy. This is merely a theory, as no known individual has ever achieved such a state. Indeed, it's not known if Ascension is even possible. But it is suspected that individuals who achieve Ascension would be virtual gods.

The Scale
All abilities stack - an individual of Level 7 has the abilities of Levels 2-6, in addition to whatever Level 7 provides.
 * Level 0: Inanimate object.
 * Level 1: "Normal" - no psionic abilities at all.
 * Level 2: The individual has an uncanny ability to read the emotions of others.
 * Level 3: The individual has a limited ability to read minds - it requires intense focus and can only be done on those close by. Strong-willed individuals or other Psis can resist it.
 * Level 4: The thoughts of non-Psis can be read very easily, though it can still be resisted. Individuals at level 4 can also speak to others in a limited fashion through telepathy - not words per-se, but mostly concepts or images.
 * Level 5: A limited degree of telekinesis is now possible - individuals can manipulate objects weighing up to 20 kilograms up to 5 meters away. Conversation entirely through telepathy is now possible.
 * Level 6: Telekinetic ability is effectively doubled. Objects weighing 40 kilograms can be manipulated up to 10 meters away. Individuals now have the ability to very subtly influence the thoughts of weak-willed individuals. Anyone above level 1 on the PSI scale is able to resist this effect.
 * Level 7: Telekinetic ability is again doubled. Subtle mental influence is now able to be exerted over individuals of all lower PSI levels. However, the higher the PSI level, the weaker the influence is. Those measuring Level 1 (generally the majority of people) are not able to be directly controlled, but a great deal of influence is able to be exerted.
 * Level 8: Telekinetic abilities double again. Individuals at this level are now capable of directly controlling the minds of non-Psis, albeit with extreme effort.
 * Level 9: The individual will have a very limited ability to "sense" several seconds into the future. This ability manifests itself as a simple "gut feeling". No specific details can be discerned, but it would be possible, for instance, to know that a car accident is about to happen; the details would remain unknown, however. Telekinetic ability is again doubled.
 * Level 10: Individuals can now sense what will happen a few minutes before it actually happens. The closer the event is to the present, the clearer the details will be. An event five minutes away will have no discernible details, but one thirty seconds away is extremely vivid in the mind of the individual. Telekinetic ability is again doubled.
 * Level 11: Unknown
 * Level 12: Unknown
 * Level 13: Unknown
 * Level 14: Unknown
 * Level 15: Individuals at this stage become beings of pure psionic energy, able to bend space-time to their will. Their abilities manifest in the form of shapeshifting, teleportation over stellar scale distances, direct mind-control of anyone at a lower PSI level than 13, extremely advanced telekinetic abilities, and precognition able to see several hours into the future. This level is purely theoretical and is near-impossible to attain.