How does "Eat Lead!" affect your chances of success?
Using the standard difficulty Night of the Zealot chaos token pool:
+1, 0, 0, –1, –1, –1, –2, –2, –3, –4, skull, skull, hood, tablet, auto-fail, elder sign; with 1 ghoul at your location and assuming the elder sign gives at least +1
Here are the odds. For each, the numbers give your stat versus difficulty, percent chance of success without "Eat Lead!" --> percent chance with "Eat lead", relative risk reduction (how much it decreases chances of failing), absolute risk reduction (how often it makes a difference):
- 4+, 93.75% --> 100%, infinite (can't fail), 6.25%
- 3+, 87.5% --> 99.6%, 30, 12,1%
- 2+, 81.25% --> 97.5%, 7.5, 16.25%
- 1+, 62.5% --> 87.5%, 3, 25%
- 0, 25% --> 45%, 1.36, 20%
- -1, 12.5% --> 24.2%, 1.15, 11.7%
(Sorry about the error with the first post, my new analysis changes my impression significantly.)
As you can see, "Eat Lead!" decreases your chance of failing considerably, especially when you're already at a disadvantage. This means that if the penalty for failing is really bad, "Eat Lead!" can almost guarantee you don't get burned. However, the effect usually doesn't do anything, since the absolute risk reduction is never more than 25%. So the analysis confirms the intuition that the best use is for really bad penalties.
Is "Eat Lead!" worth using? I think most investigators won't use it, because they don't have extra bullets to spare. Personally, I also think that the chances of failing are part of the fun of the game and I don't like the uber chaos-bag manipulating strategy (e.g. Protective Incantation, Seal of the Seventh Sign. So I think I will only use this in versions of Diana Stanley that have firearms, since she also gets the resource/card/willpower bonus that puts the card over the top.