Extra Effort Costs for Psionic Powers - pls help

[Thökk]

Hey!

Page 7 of GURPS Psionic Powers says following:

"You must determine what level of power you’re trying to attain before rolling. Then, pay 2 FP and make an extra effort roll – this is a Will based skill roll, with a penalty of -1 for every 10% increase in level (or fraction thereof) that you are trying to attain."

"Example: ...with Telesend 4. She’s now convinced he’s out of her normal range. She decides to use extra effort to raise her Telesend (p. 60) to level 5, a 25% increase."

I don't get what it means by "10% increase in level". 10% of what? Point cost?
I don't get how it was calculated that extra effort from 4 to 5 here costs 25%.

Can somebody clarify this rule to me, please.

P.S. How do I calculate extra effort to get from 1 to 5? From 4 to 9? Can you walk me through it?

[malloyd]

Originally Posted by Thökk

I don't get how it was calculated that extra effort from 4 to 5 here costs 25%.

Can somebody clarify this rule to me, please.

P.S. How do I calculate extra effort to get from 1 to 5? From 4 to 9? Can you walk me through it?

It works on the numerical levels, which Psionic Powers happen to use, though most of GURPS does not. You calculate it as 100% (higher/lower -1), so 5 is 1.25 (125%) x 4, or a 25% increase. 5 is 5.00 (500%) x 1, or a 400% increase. 9 is 2.25 x 4, or a 125% increase.

[Thökk]

Thank you!

[Thökk]

Originally Posted by malloyd

It works on the numerical levels, which Psionic Powers happen to use, though most of GURPS does not. You calculate it as 100% (higher/lower -1), so 5 is 1.25 (125%) x 4, or a 25% increase. 5 is 5.00 (500%) x 1, or a 400% increase. 9 is 2.25 x 4, or a 125% increase.

So, a consequence of this, as I understand it, going from Ability level 10 to 11 has a trivial -1 penalty, while from 1 to 2 gives almost impossible to beat -10 without a substantial Will or skill investment.

[Shimmin Beg]

Originally Posted by Thökk

So, a consequence of this, as I understand it, going from Ability level 10 to 11 has a trivial -1 penalty, while from 1 to 2 gives almost impossible to beat -10 without a substantial Will or skill investment.

That's as I understand it. As with enhancing attributes, it ensures that you can't simply buy the first level of various abilities and rely on boosting them to full power. The psi rules are actually more generous, normal Extra Effort being -1 per 5% increase.

The system of levels does create a few break points where a high-Will character can save points by taking that risk. E.g. Damage Control 3 is 32 points, DC4 jumps to 64 points but is only a 33% increase in level, so if you're only occasionally dealing with (say) burning damage, you can save your points and gamble on making the roll to halve it.
(for those without Psionic Powers, DC3 doesn't help with burning, while DC4 halves it)