How do I get better at drafting in Magic without 7 other people in the same room as me?
What I end up doing is watching videos of pros drafting, reading about opinions on each of the cards in the latest set, listening to podcasts, drafting on MTGO and through draft simulators when I’m at work or on the toilet.☺
There are several drafting simulators available right now. Most are on the web but a few are available on mobile devices. Are they helpful or hurtful to my skills? At the very least I am getting more familiar with the cards in the set, but are the cards that the AI pick realistic in an actual draft?
We are working at 5 Color Combo to try to create a realistic experience in our drafting simulator app and I want to share how we are doing that.
What we have so far
I want to break down the way that 5 Color Combo has worked on making sure the AI picks are as realistic as possible. It is not perfect and still needs some tweaking, but it will get better as time goes on.
At a high level we assign what we call a “Pick Value” to each card based on data from previous drafts, how many cards the user has picked so far, and what kind of cards the user has picked so far.
Determining Pick Value
The way we determine the Pick Value of a card is based on 4 different metrics.
- How close is the card to a first pick vs a last pick?
- Does the card fit into the colors drafted in so far?
- Would a creature or noncreature card be better?
- Does the card fit into the overall mana curve of the deck?
We try to best answer these questions by backing up the decision with lots of data. With the completion of each draft, data is gathered on when in the draft each card was picked and what the overall deck structure ended up as.
The AI is Playing Golf
The first metric is how close the card is to a first pick. For example, if the AI has the first booster pack that looks like the following, how does it know what to pick?
Citadel Siege (0.12) would be the better pick than Monastery Siege (0.22) but the value added of blue (0.38) brings Monastery Siege to an overall (0.50) versus the value added of white (0.71) which brings Citadel Siege to (0.83). Remember the AI is playing golf so it will pick Monastery in this situation.
We did find with Khans of Tarkir that the algorithm would break down a bit when comparing to multicolor and no color cards. We have addressed this by looking at the decks these cards are placed in and assigning color values based on that data. For example, the AI has noticed that Witness of the Ages has been put into Temur colors and tends to put it into those colors.
Card Type & Mana Cost
To further add into the picking algorithm the type of cards that are picked over time fall into an ideal range of where the deck needs to be. If the AI is heavily picking creatures, needing noncreature spells will outweigh a card’s inherit pick order.
A similar algorithm is made for picking cards effectively to fill out a natural curve that works best for the developing deck.
This is not a perfect algorithm. Khans of Tarkir has been a great set to test against because of the wedge making it harder to make sure that it’s picking multicolor cards well. Also, Morphs, Delve abilities, Convoke abilities and other alternate mana costs do not play into the AI picking a card yet.
Improving the Algorithm
We are looking at ways to make the algorithm more and more realistic. We want this deck drafting app to be the best and most realistic draft simulator experience available. We are looking at putting different weights on card rarities, if the card is rare and has the same 1st pick ratio that a common has, it could resolve to a higher Pick Value because it only shows up 1/15 times rather than 10/15.
We also want to have a way to evaluate if all the cards picked so far by the end of a booster pack have high value as a group and help determine if the AI should consider switching to a new color if there are cards worth it during the second round of picks.
The more data we gather the better the AI will get at picking realistic. I look forward to giving the Magic community a valuable tool to use in getting better at drafting!
Trent Ellingsen (Software Engineer)
5 Color Combo Team