The NBA 2021-22-- What a Year!

Introduction

In this project, I’m pretending to be interviewed by the Boston Celtics of the NBA for a Junior Data Analyst Role. I enjoyed the challenge of this project because I know little about basketball and had to work on my research skills to develop enough domain expertise so that I could make sense of the data. This is good practice for future analyst roles where I will also need to dive in and develop subject matter knowledge in order to offer useful insights.

The Data

I went to basketball.reference.com site and downloaded all player stats for the 2021-2022 season. There were 813 rows but only 605 distinct players. There were multiple columns. Some of the important ones are player, position, team, points, assists, total rebounds, 3-point shot percentage, and personal fouls. I uploaded the data to Tableau while also working with and referring to the Excel file. The data is not clean. Since some players were traded during the season, their names appear three or more times in the player field—once for each team they played on and once for their total stats as shown below.

?I applied conditional formatting in Excel to highlight this and filtered out the duplicates within Tableau as needed so that each player was reported only once. I didn’t delete duplicates in Excel because sometimes I wanted aggregate records for a player (indicated by their team name being ‘TOT’ or total) and sometimes I wanted complete team records and needed these players and their contributions credited to the team they were on at the time.

Key Insights - summarized in story on Tableau Public

• There are 13 players that were only with the Boston Celtics for part of the year, indicating a team in flux without a settled starting line-up. In contrast, the Golden State Warriors only had one roster change/trade during the same year.
• There is a relatively strong positive correlation between the number of points and the number of assists.
• Players with the highest rebounds have fewer assists than other players with similar points.
• Point guards have more assists than other players with the same total points.
• Nikola Jokic’ is an outlier. He is a center who has a lot of points and rebounds but also a lot of assists.
• Frequently the center has a low 3-point percentage. Boston exhibited solid performance. Their averages, per position, were all good to excellent.
• Centers are likely to commit a lot of personal fouls. Celtics centers don’t have a high number of personal fouls but their point guards do.
• The distribution of scoring varies a lot from team to team. Golden State has 4 main scorers and Boston has only two.

The Interview Context/Analysis

Task 1:

In the interview context, I was first asked to produce insights into how different players performed last season to evaluate potential free-agent signings.?Evaluating players for possible free-agent signings is particularly important to the Boston Celtics. This is a franchise with a storied history of basketball success in a city that expects greatness in its basketball team.

Despite being a Boston native, I know very little about basketball so I used this website (https://jr.nba.com/basketball-positions/) which explained the positions and gave abbreviations. This helped me make sense of the data.

The main players on the Boston Celtics during the 2021-2022 season were centers Robert Williams and Alex Horford, power forward Grant Williams, shooting guards Romeo Langford and Dennis Schroder, small forwards Jayson Tatum, Jaylen Brown, and Aaron Nesmith and point guards Marcus Smith and Payton Pritchard. There are 13 players that were only with the team part of the year, indicating a team in flux without a settled starting line-up. In contrast, the Golden State Warriors only had one roster change/trade during the same year. Despite this lack of consistency, Boston came in second for the year, losing in the playoff finals to the Golden State Warriors. Trading and curating for the best possible team was an important strategy for Boston in the 2021-2022 season and will likely remain so for the next season.

The Boston Celtics organization is interested in how different players performed on total points, total assists, and total rebounds so they can compare their team’s players to overall league trends. They’d also like to be able to evaluate performance by position.?

I made a bubble plot showcasing this.?I first made a scatter plot of points versus assists and then added the variable for total rebounds, using the size of the scatter plot’s dots to represent this. I then added a color for each position.

From this, it appears that higher-scoring players also have more assists as there is a relatively strong positive correlation between the number of points and the number of assists. The players with the highest rebounds seem to sit below the general trend line (shown as a dotted line), meaning they seem to have fewer assists than other players with similar points. This makes sense since a player who has a lot of assists is a playmaker and is not always right in front of the basket to get the rebounds. Some of their points, in fact, probably come from points scored on offensive rebounds. This is reinforced by noting that many of the high rebound, low assist, players are centers (blue) or power forwards (orange).

On the other hand, the point guards (green) tend to cluster above the general trend line, meaning they have more assists than other players with the same total points. They also do not appear to have a lot of rebounds.?This also makes sense. The point guards run the offense and are known for dribbling and passing, hence their high rate of assists and their low rate of rebounds. They should be high in points and assists but they are not in at the basket to grab the rebounds.

There are a few interesting outliers. One is Nikola Jokic’. He is a center and he has a lot of points and rebounds but also a lot of assists, which is not common for centers. He must be “all over the court” to achieve this.

Trae Young and Chris Paul also stand out for their incredibly high number of assists, and Trae Young in addition is right at the top in scoring.?Both are point guards and thus, do not have a large number of rebounds. Draymond Green has considerably more assists than other power forwards but is not high in points, so the role he plays for his team is likely to be a bit closer to the basket than other power forwards.

Task 2:

I was asked to create, for the assistant coach, a visual that can be printed out and used for reference to understand where the best 3-point shooters are.

There are 30 teams with 5 different positions for a total of 150 different values to show. To create a simple visual for the coaching staff, I decided to create a heatmap where each row represents a team and each column represents a position. Each cell shows the average 3-point percentage of that position on that team.? I then added color.?Knowing ahead of time that a team has a really effective 3-point shooter will allow the coach to make decisions about defensive strategies and whether to go for a man-to-man or zone defense.

As we can see, frequently the center has a low 3-point percentage. But occasionally there is an outlier, like the centers for the San Antonio Spurs who have an average of 45% on three-point shots and are the most consistent three-point shooters on their team. Overall, Boston’s players exhibited solid performance in this area. The averages, per position, were all in the good to excellent zone in comparison to other teams.

Tasks 3 and 4:

I made a bubble plot and a heat map for personal fouls as well. Personal fouls can often be the result of very aggressive play but can also be the result of players being a bit hot-headed. As a coach, it is helpful to know if there are players who are likely to foul. Because fouls can create scoring opportunities for the other team or can cause a player to leave the game, a player’s propensity to foul is something important for coaches to monitor.

Both visuals indicate that centers are likely to commit a lot of personal fouls, which makes sense since they are at the boards fighting for rebounds. They are much more likely to have physical contact and accidentally foul. There are some interesting outliers, such as LeBron James, who has a low number of personal fouls for a center. This could potentially be due to his fame and referees being reluctant to call fouls on him or it could be due to his relatively small number of rebounds for a center. He possibly doesn’t play in the key and aggressively grab rebounds as often as other centers. On the other hand, Jae’Sean Tate and Jaren Jackson, Jr. both have very high numbers of personal fouls, even for a power forward. Jayson Tatum, the small forward for the Celtics, has very few personal fouls for a player with so many points.?That is a good thing for the Celtics. The Celtics' centers don’t have a high number of personal fouls (unlike most other teams) but their point guards do.?Since both positions play inside, it appears that the point guards are more aggressively grabbing for the boards than the team’s center is, which is unusual in the league.

Task 5:

I needed to create a visual illuminating each team’s total points and scoring distribution. I created a stacked bar chart so I could break down points by player. This enables the coaches to see who the biggest scoring threats are, by team, and to grasp how scoring is distributed within a team.

The distribution of scoring varies a lot from team to team. We can see that the Indiana Pacers have very evenly distributed scoring whereas the Golden State Warriors have 4 main scorers and Boston has only two, which makes sense since so few of the starting five on the Celtics played for the team all year. A reasonable goal for Boston is to increase stability in 2022-2023 and have more evenly distributed scoring, like that of the Warriors.

Task 6:

The team’s general manager wants to improve the team's assist numbers for this upcoming season and would like to know what players had the most assists in every position. I created a visualization to help them evaluate the league market in assists. The visualization shows a tree map of all players, grouped by position, and their total assists.?The larger the area in the tree map, the larger the number of assists. A general manager can just hover over the map and find the number of assists for the season for any player. Trae Young and Nikola Jokic' are outliers in their positions.

Task 7:

As a final aspect of my analysis, I was asked to update the analytics division about what I’ve been working on. I decided to create a Tableau story to present my data and my analysis.

Recap and Insights

Some insights and recommendations for the Celtics:

• Golden State has 4 main scorers and Boston has only two, which makes sense since so few of the starting five on the Celtics played for the team all year. A goal for Boston would be to increase stability in 2022-2023 and have more evenly distributed scoring, like that of the Warriors.
• Jayson Tatum, the small forward for the Celtics, has very few personal fouls for a player with so many points.?That is a good thing for the Celtics.
• The Celtics' centers don’t have a high number of personal fouls (unlike most other teams) but their point guards do.?Since both positions play inside, it appears that the point guards are more aggressively grabbing for the boards than the team’s center is, which is unusual in the league. This may or may not be a good thing for the Celtics. The coaching staff should consider the reasons for this and reevaluate the role of its point guards.
• 3-point shooting is a team strength. Overall, Boston’s players exhibited solid performance in this area. The averages, per position, were all in the good to excellent zone in comparison to other teams.
• If the general manager wants to contract players high in assists, Trae Young is the player to get. If he is not available on the free agent market, the general manager can refer to the tree map to find other players with high numbers of assists.
• This is my first Tableau story. Please check it out on Tableau Public.

Thank you so much for reading my project. Suggestions are welcome. If you have any questions, feel free to comment below or reach out to me via email at [email protected] or connect with me on?LinkedIn?or check out?my portfolio?to see my other projects.

I'm currently looking for opportunities as a data analyst. If you know of any opportunities in your network, please reach out. Thank you!