Invention success rate broken?

This is how EVE defines 44.2% chance of success. So frustrating.

Damage Control FAIL #1

9 single run Invention attempts at a DCU II
3 ten run invention attempts at a T2 Web

This looks around right.
What’s the issue here?

Come back when you’ve run at least 100 separate 10 job slots with 10 Invention attempts at a DCU II.

The percentages work out over the long run. I’ve been doing invention for almost a year now and my results are very close to the base % outcomes. And also the improved success rates when using Decryptors for T2 ship hull BPCs.


A few inventions that completed this morning:


2 really good, 1 not so good, the rest very close to expected value.

with the upcoming success chance reduction by 45% should see more of these posts


Same source as Heard on missions channel ingame - SOE 45% reduction in LP nerf

@ISD_Buldath I think we have a troll!

Probably the same guy that’s been saying trigs will start to invade mission dungeons/rooms for the last few months.

Total troll.

This comes up every so often. Been a while since I’ve seen it though.

Random is random.

Each result doesn’t affect the next. So just because you’ve had 66 failures, doesn’t mean you’re now going to get 44 successes. Over a sufficiently large sample, it averages out. Your sample is nowhere near sufficiently large.

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Eve doesn’t define anything. Universal laws of mathematics do.

See also, dice don’t have memory.

That’s 44 out of 100, bud. No sh*t you’re going to have mostly failures.

can someone tell what would be a reasonable large sample???

I mean for some (me) just wanting to invent for fun and personal use, with a run of 10 w40% success rate you should get 4.

Is there something in the mechanics that remembers i’ve tried x runs of y blueprint, so over the next 90 attempts will end up right?

It’s like flipping a coin. Each time there is a 50-50 chance of heads or tails but you can get long runs of 1 or the other. As your sample size increases you will come closer to the expected value.


“A reasonably large sample” - realistically, think of a very big number and don’t be disappointed if it isn’t big enough. And even then there’s no guarantee that it will end up as exactly 40% - it’s a probability, not a guarantee.

Each invention is an independent event - there is no memory and not “it will make up for your disappointment later”. This is very much like tossing a coin - 50% heads, 50% tails. If you get five heads in a row, then the chance of a Tail in the next toss is still 50%. What happened in the past doesn’t have an impact in the future.
This is tossing dice, not drawing cards (card drawing isn’t independent, each card drawn and discarded impacts the proportions of cards left - no fifth Ace!)

The probabilities of each outcome are predictable. If I have a 40% success rate, then if I do ten inventions, the chance of getting exactly four invention successes is 25%, the odds for 3 is 21%, for 5 it’s 20%. (i.e. about two-thirds of the time I’ll get 3,4 or 5 successful inventions).

Critically, those ten runs are also independent of the next ten runs - or even “the ten runs I also do at the same time in another invention slot”. That “invention probability” is exactly that - the probability of one invention being a success.

The whole table

Probability on N successes in 10 attempts at a 40% success rate.
I’m rounding the figures, so won’t add to 100.
p(0 succeed) = <1%
p(1 succeed) = 4%
p(2 succeed) = 12%
p(3 succeed) = 21%
p(4 succeed) = 25%
p(5 succeed) = 20%
p(6 succeed) = 11%
p(7 succeed) = 4%
p(8 succeed) = 1%
p(9 succeed) = <1%
p(all succeed) = 0.01%

There is no concept of “it will end up right”. Sometimes you are lucky, sometimes you are unlucky it should balance out over time but you may just not be lucky. That’s randomness for you.
Human Nature is that you tend to remember the Bad outcomes more strongly than the Good outcomes - which means you have a stronger “it’s not being fair to me” feeling. But that’s just subjective - the universe doesn’t care one way or the other.

And they’ve summed it up much more succinctly than me.

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