Quote:
Originally Posted by Mailanka
Note that this actually happens anyway: You get less for your points with each increase of a stat.
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Only if the GM puts an artificial ceiling on task difficulty.
Quote:
Originally Posted by Mailanka
GURPS has a bell-curve. A stat of 10 will roll successfully (assuming no modifiers) ~50% of the time. An increase of decrease of 1 point changes this by +/- 12.5 percentage points, which means you're getting about +/- 1 percentage point for 2 character points.
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This is a false way of measuring value -- there are times when value is linear in success probability, but an awful lot of times where it's not, it depends on how much of the value of skill comes from the increased chance of success, and how much comes from the risk of failure. Probably the most likely to be true measure of value is the ratio of success to failure (which tells you what sort of gambles are reasonable to take), which gives skill value roughly as follows (+1 multiple shows the
ratio of this skill level to one level lower).
Code:
Skill 4 5 6 7 8 9 10 11 12 13 14 15 16
Chance .019 .046 .092 .162 .259 .375 .5 .625 .740 .838 .908 .954 .981
S/F .019 .049 .102 .193 .35 .6 1 1.67 2.86 5.17 9.8 20.6 53.0
+1 multiple 2.57 2.10 1.90 1.81 1.7 1.67 1.67 1.71 1.81 1.90 2.10 2.57
Notably, this implies that high skills are vastly more useful than moderate skills, and that, as a ratio, the endpoints matter more than the middle.