[MarcoSkoll]

I apologise in advance, this post is mostly unnecessary rambling, but feel free to read it anyway.

I know many of the people on this forum are at best apprehensive about the Greco-Numeric assignment for describing psyker potential - although you may remember that PrecinctOmega suggested some improvements on the last 'Clave, which Ynek sums up here.

But nonetheless, I've been contemplating it and what it might actually mean.

One idea that came to me is that it doesn't actually describe power potential, but rarity.
Much like IQ only describes the likelihood of an individual having a given "intelligence" (let's not get into an argument about how much use IQ actually is), rather than being a number that is directly descriptive of their brainpower, perhaps the Assignment does the same.

If we start with Rho being typical, and work up the scale with each subsequent category being five times rarer than the last (although not necessarily five times more powerful), then... well, I don't really know what that exactly means, but it makes it a bit more than just a completely vague number.

I'm using five because it roughly translates to the roughly one in a billion rarity given to power levels that exceed Delta. It consequently gives a one in 400,000 rarity for power levels above Iota (where conscious control starts), which doesn't seem too implausible to me.
You can do something similar with the negative assignment levels, although those will need a much greater rarity between levels - the number 30 seems to create reasonably believable numbers.

While the rarity of a given power level can ultimately be tracked back to the power of a psyker, the idea of a logarithmic rarity scale can explain why there isn't necessarily a "top end" to the scale.

~~~~~

And yeah, I know I'm trying to put numbers on something which wasn't ever designed to take them, but it's just an idea that struck me and made me think "Hmm, that might even make sense".

[precinctomega]

I certainly makes some sense.  It would explain why some psykers are given different Assignments by different people (like Ravenor, for example, being described by different characters as both "delta" and "alpha plus"), as an assessment of a psyker rarity would be highly subjective.

However, that aspect of subjectivity does rather make one wonder why such an Assignment would ever be invented, even in the famously bureaucratic Imperium.

R.

[Alyster Wick]

I would agree with PO somewhat on this, to judge solely by rarity would seem somewhat pointless. The rating would depend upon what pool of data you're comparing the individual to and at what time period you're rating them (as the discovery of psychers similar to past psychers could potentially drop the rating of a given category, if I'm understanding you).

Also, the current rating scale seems to carry a certain level of dread with it (everyone fears the alpha level psycher) and this reading of the scale potentially neuters it. 

All in all it's an interesting thought, but I feel as though certain bits of background are best left vague so as to keep a measure of wonder.

[MarcoSkoll]

However, that aspect of subjectivity does rather make one wonder why such an Assignment would ever be invented, even in the famously bureaucratic Imperium.

It's not really that subjective. It's simply a logarithmic scale that ranks psykers by the likelihood of having a given psychic potential.

Whereas the IQ system makes it so that people of IQ 160 and above are 1 in ~31,500, the system as I put it puts people with Iota talent and above at 1 in ~400,000 births across the Imperium.

The scale does still translate to power potential. All I'm doing is suggesting how the boundaries of each category might be defined - each "letter" is drawn up so that its category will contain roughly a fifth of the number of psykers in it that the last group had...
(Consequently, for every Delta Birth, there will be five Epsilon births - for every Epsilon, there will be five Zeta births)

Also, the current rating scale seems to carry a certain level of dread with it (everyone fears the alpha level psycher) and this reading of the scale potentially neuters it.

I don't see why. Saying that an Alpha is a one in hundreds of billions level of power potential doesn't exactly make it sound nice and cuddly.

The rating would depend upon what pool of data you're comparing the individual to and at what time period you're rating them

I imagine that the Imperium has seen enough psykers to know where to put the boundaries (it's not intended to be utterly precise - more that "a Gamma psyker is about five times rarer than a Delta psyker"). There's no need to reshuffle the system every time they discover each new psyker.

I feel as though certain bits of background are best left vague so as to keep a measure of wonder.

It doesn't actually tell you much more as I've set it out - just starts talking about the rarity of each class, and as a plot defines each psyker as being as rare as the story needs them to be, then that doesn't necessarily mean much either.

[Swarbie]

I like this concept. For some reason, I've always thought certain things were rare for a reason. I mean, if Alpha-level psykers littered the ground like half-eaten apple cores, they wouldn't seem so special, would they?

I also think about psykers in this way because I think psychic power is derived from a different organisation in/amount of an individual's neurons. It makes sense to me that formations of neurons able to bear the stress from the power associated with an Alpha level psyker are extremely rare and unusual, whereas the lower levels become increasingly more common, although still uncommon.

[Alyster Wick]

I read this post relatively fast originally and upon a second read through feel rather daft for my previous post.  Consider all criticism rescinded.