I am officially done spading the pickpocket bonus mechanic. There are a few unanswered questions, such as “Does the Black Hole stack with the bonus”, “Does the bonus apply to Birdform pickpockets” and “How did GoldS get so many pebbles to drop?”
The First major obstacle was realizing the wiki was wrong, flat out wrong on the rates for most of the pickpocket only items. I spent a month and a half running a multi around the kingdom collecting data for Quarks, Little Round Pebbles, Cheap Cigar Butts and Colon Annihilation Hot Sauce. Without olfaction, and on a very cheap diet (200ish turns per day), I would see perhaps 40 – 60 monks per day, which took a while to collect enough data to feel confident with. I actually managed to snag 800 data points in just over 2 weeks, giving an observed rate of 39.13 on the pebbles. My sample size for the other pickpocket only items are much smaller, but quite obviously not the given rate by the wiki.
The Second thing was knowing how pickpocket actually worked. Normally, the game chooses the items based on the unmodified drop rate – if a sent gland has a 10% drop rate, you could also pickpocket it 10% of the time. It gets more complicated when the monster has more items available to steal – if the monster has two (unique) 25% base item drops, the rate of any one of those items is 21%. In the case of the Monks, who have 3 items that can be pickpocketed, an item that was observed at 39.13% would have an (effective) base drop of 47% (most likely 50%) unless…
The Third thing was that I wasn’t exactly sure how pickpocket only items were chosen. I could easily see it being a separate roll, perhaps done before or after the game rolls for normal drops. In fact, I quite clearly remember someone telling me this was the way it worked when i was a newb. This, in fact, is not the way it works. Rather that it being a “second” pickpocket roll, pickpocket only items are chosen alongside the normal drops. I also wasn’t sure if pickpocket only items had the bonus apply to them.
My data
Number of Ancient Insane Monks: 800
number of stones pickpocketed: 313 (39.13%)
WITH +70 pickpocket bonus
number of monks : 224
number of pebbles: 129 (57.6%)
number of sakes:45 (20%)
number of cereal: 25 (11%)
The model predicts a 59% observed rate for the pebble if it was rolled alongside the other drops and if the pp bonus applied. Sake was predicted at 18% and the cereal at 10%.
It’s also worth mentioning that since pickpocket only items are chosen alongside the other possible drops, all of the observed rates the wiki lists that end in 0 or 5 are flat out wrong. The base rate should be in an increment of 5, and the effective “base rate” rate should be calculated from that, so it can be gauged how effective pickpocket bonuses will be. The good news is that the difference is very small for smaller numbers and monsters with fewer drops.