Ever since I started playing this game I’ve heard the suggestion that when feeding your heroes, it’s best to do 10 cards at a time to maximize the chance of bumping up their special skill. But I’ve never understood the math and statistics behind that theory, and rather than continuing to torment my team and peer support with my stubborn questions, I asked a friend (a physics professor) to lay it out for me. Turns out everyone’s right, sort of!
For this example, let’s say we’re feeding 1* heroes to the same color hero. Individually, the chances of increasing special skill is 2%. Feeding ten at once increases this to 20%.
It might be easier to imagine this as physical odds instead of percentages. In option one (feeding ten at once), you can pick from a jar with 5 tickets, and one is a winner. In option two (feeding ten one at a time), you pick 10 times from 10 different jars - each containing 50 tickets, with only one being a winning ticket. That is, one 1/5, or ten 1/50s.
In option one, you clearly have an 80% chance of not drawing a winner. In option two, the math is a little trickier - it’s 49/50 to the 10th power, or 81.7% chance of failure. So, the difference in risk is 1.7%, and option one seems better, if not significantly so. But, my friend still insisted you should take option two - and here’s why.
The math above doesn’t account for the chance of multiple wins in the 10-jar scenario. That is, the potential reward is significantly higher. You could, however unlikely it may be, feed 10 heroes one at a time and get a special skill bump on every single one (well, the first 8, at least). This potential reward factor compounds almost exponentially over time. Considering we’re feeding heroes not just dozens, but sometimes hundreds of cards - doing it individually appears to be the way to go.
Before I posted this I searched the forum to make sure this hasn’t been discussed before, and it seems it has several months ago in a comment on the post linked below. Full credit to this contributor for getting there first, but I wanted to bring this topic to full light again:
Thanks for reading all the way through this boring math stuff, and if anyone sees fault in the logic here, please let me know! If there is an advantage one way or another, I think it’s important we all know about it!
UPDATE 1/17/19 Due to the latest game update, MAXED 3s now have a 5x chance to level up their special. That is, feeding five 2s of the same color or ten 1*s of the same color will produce a 100% chance of special level up. While I believe my math still stands for how best to get them TO that point, it’s now very quick and easy to save up the 5/10 at the end and make up for any missed special leveling - and in such cases SHOULD be fed all at once. (Incidentally, awesome update, thank you SG!)