Thread:ZDee/@comment-1264592-20130501155822/@comment-4085424-20130506003914

For luck-based challenges with a rare success, I suppose we'll record the chances of all three outcomes? i.e.
 * success % = #succ/(#succ+#rare+#fail)
 * rare % = #rare/(#succ+#rare+#fail)
 * failure % = #fail/(#succ+#rare+#fail)

The other alternative would be separating the chance of success vs. failure and rare success vs. regular success: which seems much less intuitive to me.
 * success % = (#succ+#rare)/(#succ+#rare+#fail)
 * rare % = #rare/(#succ+#rare)