map balance - comparing pro and bot balance
I started to think about fancy ways to normalize map balance data so that the numbers could be compared—and then I realized, who the hell cares? The data’s not good enough in the first place, at least the bot data, which is based on only 21 bots with idiosyncratic play styles and big race imbalances regardless of the maps. We can only get a general idea of the comparison anyway.
So I decided on a simple subtraction of the average from each map balance number, so that a map with average balance has normalized balance 0%. Then we can compare maps to see if they have similar relative balance for pros and bots. After normalization, TvZ > 0 means that terran did better than average on that map, and TvZ < 0 means that terran did worse.
| map | TvZ | ZvP | PvT | |||
|---|---|---|---|---|---|---|
| pro | bot | pro | bot | pro | bot | |
| Benzene | 10.8% | -2.9% | -5.3% | 1.3% | -5.1% | -0.4% |
| Destination | -1.0% | -1.9% | 2.6% | 2.3% | 0.7% | -0.4% |
| Heartbreak Ridge | -4.7% | 3.1% | 2.2% | -0.7% | 5.3% | -3.4% |
| Aztec | -14.3% | -1.9% | -4.4% | 1.3% | 11.6% | -0.4% |
| Tau Cross | -3.3% | -0.9% | -4.4% | -0.7% | -1.8% | -0.4% |
| Andromeda | -10.6% | 1.1% | 4.4% | -1.7% | 3.8% | -4.4% |
| Circuit Breaker | -0.4% | -0.9% | -2.6% | -1.7% | -0.8% | 2.6% |
| Empire of the Sun | 10.9% | -4.9% | -4.4% | -1.7% | -2.7% | 0.6% |
| Fortress | 11.0% | 8.1% | 12.3% | -0.7% | -2.6% | 4.6% |
| Python | 1.9% | 1.1% | -0.5% | 2.3% | -8.0% | 1.6% |
There’s no “overall” row because, after normalization, it’s just a row of zeroes. Also, as I mentioned, the sizes of the imbalances can’t be compared directly. A relative balance of -5% in the bot ZvP column (average balance 71%) doesn’t mean the same thing as -5% in the pro ZvP column (average balance 54.4%).
No convincing pattern is visible. The pro and bot columns have the same sign in 12 cases, which is not distinguishable from 50% (15 cases). Sometimes a pro map with a large imbalance has a large imbalance for bots too; sometimes not. Here’s a scatter chart with relative pro balance on the x-axis and relative bot balance on the y. Remember that the signs are arbitrary: We arbitrarily chose to compare TvZ rather than ZvT, so + and - were chosen arbitrarily. If your eyes think they see a pattern, flip one or two of the symbol sets around one axis or the other before you decide it’s real.
What does it all mean in practice? There are some maps with apparent imbalances, which means we should have map pools large enough that imbalances tend to average out. Most maps are not far from balanced, so 10 maps should be enough; the 5 maps of CIG 2016 do not seem enough. Other than that, there’s no reason to change how we select maps. We don’t know whether last year’s relative map balances will carry over to this year, when the skill of the top bots is greater and they are terran rather than zerg. The main conclusion is the same as the conclusion of all studies since the invention of science: More research is needed!
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imp on :
Two examples:
1) a bot relying on muta-micro will have an advantage on maps where mutas can be abused. On worse maps, it will still play mutas.
2) A map like Lost Temple (Terran-favored for pro players) may look balanced for bots simply because bots do not take advantage of the cliffs above the naturals.
krasi0 on :