As a student at the Flatiron School, I decided to continue the work from my
previous module 4 project and try to predict March Madness outcomes for my Capstone Project. I wasn't particularly happy with my results and wanted to see if I could improve my model from before. I ended up starting over completely and didn't use any of the code from my previous attempt.
- Most of the data for this project was obtained from Kaggle. Additional data for this project was obtained from Kaggle users and from websites sited at the bottom of this page.
- This notebook contains much of the initial feature engineering that I conducted. The main features created here were season averages for each team going into that years tournament.
- This notebook is exclusively dedicated to engineering the Massey Ordinals features.
- This notebook is exclusively dedicated to engineerint the TrueSkill Rating feature.
- This notebook is dedicated to engineering features that capture the distance from each team's home town to the location of the game site and also the difference in elevation between the two.
- This notebook contains all of the modeling work that I conducted for this project. Some additional feature engineering is also contained in this notebook.
- Using the data from Kaggle, and other outside sources, I am attempting to predict the outcomes of NCAA Men's Basketball Tournament games. I intend to use this information to be able to place bets on an NCAA Tournament Bracket in future years.
The metrics that I am using for this project are log loss and accuracy. I used both of these metrics because they each provide useful
information that the other doesn't communicate. The log loss metric is on a scale from 0 to 1, with 0 being perfectly right and 1 being
perfectly wrong. The log loss is useful because it takes in the probability values that I generated with my model and compares them to
the outcome that I predicted. For example, I used a value of 1 to indicate that team 1 won a particular game. If I predicted the that the
probability that team 1 would win to be 0.75, I would get an even better log loss score if I had predicted the probability to be 0.8.
How confident you are influences the model. However, it doesn't exactly tell you how many predictions were correct, meaning, a probability
greater than 0.5.
Therefore, I used a second metric, accuracy. Accuracy is simply how many correct predictions I made divided by the total number of games.
This metric is useful because it is very easy to understand and gives you the most important information. However, I thought that the
logloss metric would still be useful, because ideally I would like my predictions to have a high degree of confidence.
The first thing that I did after deciding on my project was to look at what others had done. Due to this being an annual Kaggle competition there were numerous notebooks that others had posted laying out how they approached this problem. I was fortunate to have access to so many different ideas and I ended up taking ideas from a few different notebooks and incorporating them into my project. I listed the notebooks that I used at the bottom of this page.
Obtain Data/Clean Data
The next step I took was to obtain the data that I wanted to use for my project. Fortunately, much of the data that I wanted to use was made easily available on the Kaggle competition page. The dataset of the utmost importance was the dataset that contained the outcomes of NCAA Tournament games, along with all of the traditional boxscore statistics for those games. I also wanted to use the same type of data from regular season games in order to base my tournament predictions on how the teams performed during the regular season. Kaggle also provided data on tournament seeds, the location of where each tournament game was played, different spellings of team names, massey ordinals, and the conferences that each team played in. I engineered features using all of the previously listed data.
I also obtained some data from outside sources. One dataset that I was eager to use was from Kenpom.com. This is a website that provides advanced college basketball analytics, however the data that I wanted to use was behind a paywall. Fortunately, a user on Kaggle posted much of the data that I wanted to use. I also turned to Kaggle users to provide data on the latitudes, longitudes, and elevations of the cities where the tournament games were played and also the cities and towns that each university was located in.
My final data collection step was to obtain data that was missing from the previously mentioned datasets. One such dataset was the one containing game locations. The dataset only went back to 2010 while I was hoping to use data going back to 2003. Therefore, I scraped the remaining game locations from basketball-reference.com. I was also missing data on the latitudes, longitudes, and elevations of some of the cities in my datasets, and due to the low number of missing values I decided to enter in the values manually.
Fortunately, most of the data was relatively clean, so asside from having to scrape and manually add a small amount of data I did not have to do much additional data cleaning.
Most of the work that I did on this project was the feature engineering step, resulting in dozens of features. The largest share of features came from finding season averages for each team. In order to do this I used the data comprising box score statistics for every game for every team and finding the season averages for each of those statistics. This includes statistics like defensive rebounds, offensive rebounds, blocked shots, steals, free throws made, free throws attempted, etc. In addition to these I created features for:
- Wins over the last 15 days of the regular season
- Tournament Seed
- Kenpom stastistics (adjusted offensive and defensive efficiency, adjusted net efficiency, and a measure for luck)
- Win/loss target feature (1 if team 1 won the game, 0 if team 1 lost)
- Number of wins against top 25 teams, with the top 25 being determined by adjusted net efficiency
- Massey Ordinals. The dataset includes a large number of rating systems and each team's ratings throughout the season. I found which rating systems were the best predictors of outcomes and took the top 4 and averaged their results.
- TrueSkill rating. This is a rating system developed by microsoft to be used in their video games to determine team and player quality.
- Each teams traveling distance from the college's hometown to the location where the game is played.
- The difference in elevation between a college's hometown and the game location.
I also created a seperate dataset for 2019 data which included all of the previously mentioned features.
I then had to merge each feature onto the original dataframe.
I used a combination of two models for my final results. I used both a Logistic Regression and an XGBoost Classification model. After
obtaining predictions for both of these models I found that weighting the Logistic Regression model's predictions by 0.7 and the
XGBoost model's by 0.3 produced the best results.
I validated the model by training on seasons prior to the 2019 season and using the data from 2019 to test the model on.
- Difficult to pick upsets, particularly among the top seeded teams.
- Whether a feature is important depends on the model being used. There was quite a bit of difference between the logisitic regression model and the XGBoost model.
- Limiting data to only the past few years improved my results. I found that the optimal results came when I limited the training set to only the past 3 years of tournament games.
- Best model picks 55 winners correctly, missing 12 for an accuracy of 0.82, with a log loss of 0.41.
The first step in reproducing my results would be to obtain the data. I have attached all the data that I used in my project in a folder labeled data. However, if someone wished to use my notebook for the 2021 NCAA Tournament they would need to get an updated dataset. The first place to look would be Kaggle, where they host a competition every year to predict the tournament outcomes. I also attained the Kenpom data from a user on Kaggle, so in order to get updated Kenpom data you would either need to find another user who had posted this data or scrape it from the Kenpom website.
Once all data is obtained next step is feature engineering. To reproduce the results that I produced I would recommend running my notebooks in the following order; Data Preparation, Massey Ordinals, TrueSkill, and Game Location. Finally, the last step would be to run Modeling Notebook 2.
I would like to try predicting on all college basketball games for the past few years, instead of predicting on season averages dating
back to 2003. I found that my predictions were getting better when I limited the training data to only the past few years. Therefore,
this leads me to believe that college basketball changes a bit over time. The reason I didn't do this initially was that I would be
unable to use some of my best predicting metrics. The data that I have for the Kenpom metrics only has end of year statistics, and
therefore I would be unable to use them during the regular season. Furthermore, tournament seed was a useful statistic that I wouldn't be
able to use either. Despite these reasons, I would still like to attempt to model it because it would allow me to have a much larger data
set, all being data from the recent past.
I would also like to try to use individual player quality as a factor in finding the quality of a team. Doing this would both allow
me to try modeling the data in a different way, but it would also allow me to factor in player injuries into my predictions. If a team's
star player gets injured before the NCAA tournament my model would probably prove inadequate at predicting that team's results. By
rating players individually, I would be able to attempt to estimate the quality of the team without said player be reweighting the
contributions of other players.
I would also like to try and obtain information from other sources that I did not have for this project. One dataset that I used,
Kenpom data, was provided by a user on Kaggle. However, there is more data on the Kenpom website behind a paywall. I am considering
subscribing to the site to try out some of their advanced statistics.
I would also like to try more models and different ways of combining them to see if I can capture the strengths of each one.