Is there a place that lays out the math for skills? For example, if a skill says it provides a 2% bonus to yield, is that 2% on the untrained amount each time, or is it 2% of the previous skill level?

That’s just an example, mind you, and I’m more interested if someone has dug into the math and figured out how the numbers are calculated.

What I really like is that when you look at the attribute details of a fit, if you have skills (or other installed fits) that enhance the fit you will see that noted.

The number on the right will be highlighted in green and when you mouse over the number a small window will show what skills/fits apply and how much the basic level is so you can see how much benefit you’re getting.

That’s true in some aspects. In others, I don’t think it’s noted. For example, if I look at an ore’s Industry tab under “Show Info,” it seems to show the mineral quantities I can expect with my current reprocessing skills, with no indication I’m getting any kind of buff from trained skills.

Ore processing also depends on what station you’re at, your standing with the corp if it’s an NPC station, other things too I think.

For example, I have Reprocessing 4 and Reprocessing Efficiency 4 yet even at an NPC station I have good standings at I only get 50%. However, at a player station I often use I get 65.4%.

(edit)
Also depends if you have trained into any specific/specialty ore processing.

That’s true, it does depend on the station and a number of variables. When I’m in an asteroid field and look at what’s in my hold, however, the industry numbers are formatted the same as “base stats,” without reflecting Reprocessing V and Reprocessing Efficiency IV, which I have.

It would be nice if, when I hover over those numbers, I could see the base stat to get an idea of what kind of benefits I’m getting from my skills, just to be able to understand the math better.

The skill math is pretty simple. I’m not sure why you would find it confusing or subject to interpretation. There are cases (e.g. damage resistance bonuses) where it may not be clear the interpretation of the bonus itself, i.e. what the bonus really means, but the per level skill math, which is what you appear to be asking about, is straightforward in all cases.

If a skill provides say a 5% bonus per level to some attribute, then it does exactly that, provide 5% bonus at L1, 10% bonus at L2, 15% bonus at L3, and so on. There is no other possible interpretation to what the description of the skill bonus says…

Now, this means the attribute in question is modified by a multiplicative factor which in the example above would be:

1.05 at L1
1.10 at L2
1.15 at L3

and so on.

If an attribute is modified by more than one skill, you just apply the multiplicative factor of each skill to compute the result. Since multiplication is associative and commutative, it doesn’t matter in which order you apply those factors.

Thus, an attribute that would be increased by say 15% because of some skill and by say 20% because of some other skill would be modified by a factor:

Skills that increase per level are additive, not multiplicative.

Your result is correct, that at level 3 of 10% per level you have a 30% multiplier, or in other words, the original value times 1.3. But your calculation suggests a multiplicative increase per level.

For separate bonuses it is indeed multiplicative. 3 separate 10% bonuses would be a 1.331 multiplier for the original bonus, or 33.1%, as it is 1.1^3. If you have three modules that each increase damage by 10% it would be a 33.1% increase total… if there was no such thing as diminishing returns to make stacking similar bonuses less effective. But that’s another topic.