I know this has been asked / answered a million times but I can’t figure out how to google the question right.

Question: Take Amarr Starship Engineering. Say I want to Invent a Paladin. Required skill is level 1

So in reading the description there is no reason to train it beyond level 1 unless your going to use research agents or 1% per level in time reduction in building said Paladin.

The higher your level of Amarr Starship Engineering, the greater the chance that the invention will succeed and produce a Paladin blueprint. Invention isn’t a 100% guaranteed outcome. Depending on your skill levels and what you are inventing, only 3 or 4 runs out of 10 may succeed.

It shows in the industry window on the right hand side. Mouse over the invention percentage and it will pop up with a box showing your current skill levels and how they contribute to that percentage.

The decryptor that you use counts as well. The more expensive the decryptor, the better the chance of success. There are also decryptors that increase the number of runs, but with a lower chance of success.

of the several skills required to invent, per level, one adds 4, the others (those which require hacking) add 3 on a base of 120
so if invention needs 3 skills, and you have them all at 2, the probability is multiplied by (120+2×4+2×3+2×3/120 = 1.166