Analysis of CS:GO Win-rates

This post is going to be a little different from usual; instead of markets, we're going to look at a video game, namely, Counter-Strike: Global Offensive (CS:GO). CS:GO, like most great games, is easy to learn but deceptively hard to master. For those at are unfamiliar with the game, we'll give a quick overview below.

CS:GO is a competitive zero-sum game in which two teams of 5 players each try to win rounds. The first team to 16 points wins the game. The game is asymmetric as there are two distinct sides: the terrorists (T-side) and counter-terrorists (CT-side). After 15 rounds, each team switches sides. The goal of the T-side is to either eliminate all CT players or to plant a bomb and have it explode before the CT-side can defuse it; the CT-side wins the round if kill all the players on the T-side before the bomb is planted, if they defuse the bomb, or if time runs out on the round. this asymmetric rule-set implies that the CT-side can lose a round even if they kill all the opposing players, while the T side cannot lose if they eliminate all CT players.

In order to get a better idea of the structure of the game, let's look at a top-down perspective of one of the most famous and iconic maps, Dust2:


T-side starts the game in T-spawn and must plant their bomb at one of two locations: B-site or A-site, designated by the red areas on the map. the CTs start off in CT spawn and must try and defend these two sites. If T-side manages to break the CT defenses and plant the bomb, the remaining players on CT try and retake the bombsite (either A or B) and defuse the bomb before it explodes.

Because of the asymmetric nature of the game, I thought it would be interesting to analyze how much a kill effects the game for each side. To start off with, we'll first look at the situation where the number of players on each side is equal.

Even Match-ups

First up, let's look at the so-called even match-up, where there are an equal number of players on each team: 5v5, 4v4, etc. Using over 400,000 rounds of match data from mid-2018 (click here for the original dataset), we aggregate all rounds with even match-ups and the side that wins. From this, we can calculate a cumulative win probability for each match-up:

Even Match-ups

From the above graph, it's seems that the T-side enjoys a significant advantage. Even when the match starts, the CT-side has a less than 50% of winning the round and as trades are made (a situation where each team loses a player), the advantage the T-side has only goes up. But is this significant? Let's look at a table of CT-side win rates and their associated p-value:

CT win rate p-value players
0.48729 2.67482e-55 5
0.469768 1.17974e-151 4
0.455098 3.84482e-237 3
0.439982 1.52963e-319 2
0.430299 2.35914e-282 1

It's clear from the minuscule magnitude of the p-values that we can reject the null hypothesis, namely that each even match-up is fair: a 50% chance of each side winning the round.

All Match-ups

Now that we've established that even when each side has the same number of players the T-side has an advantage, let's consider all the possible combinations. Clearly a situation when 5 CTs are up against 4 Ts is not a fair fight (We might assume that CTs have the advantage), but unfair is it? After crunching the number for each permutation, we get the following graph:

All Permutations

Interesting! When the CTs have close to the number of players as T-side, the first kills make the most difference. A 5v5 for the CT side gives them a 48% chance of victory, but netting the first kill shifts the odds considerably to 68%. When the difference is large, the final kills have the highest percentage chance, as the chance of the CT-side winning is so low to start off with. Below is a graph of the exact figures:

1 CT 2 CT 3 CT 4 CT 5 CT # T alive
0.00218907 0.0227307 0.106122 0.274956 0.487288 5
0.00689667 0.0682988 0.235994 0.469768 0.683482 4
0.0287596 0.187184 0.455091 0.70026 0.858241 3
0.123364 0.439972 0.732706 0.893306 0.961373 2
0.430299 0.7915 0.941975 0.985024 0.9967 1
0.906434 0.989945 0.998562 0.999731 0.999873 0


I know little about professional CS:GO strategy and the data isn't taken from professional games, but we can quickly infer a couple things from the data:

  1. T-side wants to trade down as much as possible, CT never wants to trade.
  2. CT-side needs to be play very conservative, maximizing the number of players on their team that are alive.
  3. T-side wants to play in a very aggressive style in order to take map control and trade.

Anyways, this has been a fun little post to write, I hope you enjoyed it! Click here to view the GitHub project.