True, although hulls and most weapons have no accuracy bonuses, and designs will typically include the maximum attack bonuses possible with the available tech.
Given the range your ships fight at, and some knowledge of the enemy's tech level, you can get a pretty accurate baseline.
The true break-even point will be a fuzzy region around the calculated point, but if you are well on one side or the other, you can be fairly certain which of the two options (ECM-armor or shields) is best.
There are also missiles, talismans and rammers to worry about, as well as one-shot-one-kill weapons.
Given the complexity of the game, formulae like this will be a guide, rather than a law.
Before I went through the formula, I had no idea when it would be worth putting Stealth armor on a ship
