As Atlanta United, and MLS, develops deeper knowledge and use of data analytics, we’ll be taking a look behind the curtain at some of the specific stats the club values. In our new weekly content series, we examine one metric provided by StatsBomb that may not stand out on a first watch, but upon closer evaluation, is a useful tool to measure the team’s performance. This is Staying on Track presented by MARTA.
Our stat this week is talking about shot quality. Per StatsBomb, and a majority of MLS coaches, a significant principle for the game of soccer is wanting to push players to take the highest quality shots possible. A team needs to find ways of attacking that create high quality shots.
It’s a basic truth of soccer that is guided by a few principles defined by StatsBomb:
- The closer a shot is toward goal, the more likely the shot will be converted.
- Central locations are better than wide, because most of the time a central location provides a better angle and more space not covered by the opposing goalkeeper.
- At the same distance, shots taken by the foot are more likely to be converted than shots with the head.
Data-wise, the measuring stick for Atlanta United is broken down like so, measured in expected goals per shot:
- 0.1 = good chance
- 0.2 = high quality chance
The league-wide average is 0.1 expected goals per shot.
In the match against Houston Dynamo on June 15, Atlanta United created five good chances. Four of those chances had a value over 0.2 xG. (Higher quality chances have a higher xG value.)
To drive home this concept, we’re taking a look the goal scored by Daniel Ríos in the match against Houston Dynamo. The goal arrived in the 25th minute and was the second goal of the season in MLS play for Ríos.
Much like Jamal Thiaré’s goal against New York City FC, the goal Saturday started with a long punt from goalkeeper Brad Guzan that gave the striker room to run. Ríos ran down the pass and blocked Houston’s attempt back to the goalkeeper, giving Ríos a lot of space with the ball.
He backheeled a pass to Luke Brennan who then squared a low-driven cross into the center of the box. Thiago Almada had the first attempt, which was smothered by Houston goalkeeper Steve Clark. But Ríos was there to collect the rebound right at the top of the six-yard box. He hammered it home to even the match 1-1.
This was considered a high-quality chance because of several factors:
The shot itself
The shot from Ríos was high velocity. He hit the ball with his right foot, which bumps up the quality because Ríos is right-footed. The distance was 8.61 meters away from goal, a relatively short distance just outside the six-yard box. The shot impact height was zero meters because Ríos hit the ball on the ground. A goalkeeper who hadn’t just made a diving stop might be able to make a dive attempt, but Ríos had the advantage.
The lack of pressure from defenders
Clark was preoccupied with Almada’s shot, so the marked distance between Ríos and Clark was 2.24 meters. Additionally, there were only two defenders within the designated “cone” area made by the shot location and the mouth of the goal.
The angle toward goal and shot impact
When Ríos unleashed his shot he was at an angle of about 87 degrees. That’s almost a perfect right angle to the goal.
See it all come together in the video below:
One number that Atlanta United wants to improve on is the expected goals number that comes on set pieces. On the season, Atlanta United has a measure of 0.99 expected goals. The number is quite high, but they haven’t scored on as many of those chances, so that is one area where the team can improve on.
Atlanta United's Data Scientist & Analyst Arjun Balaraman contributed to this story along with Data Engineer Akshay Easwaran. Visualizations and video by Khoury Kennedy, Atlanta United's Motion Graphics Producer and Video Editor.
