This project was designed as a machine learning exercise using the spotify "hit predictor" dataset, created by Farooq Ansari. Original dataset available here.

• Purvi P. Patel
• Cristina Bardan
• Grecia Villarreal
• Heidy Guzman

• Original data
• Models (& variations) tested
• Deployed program

The dataset by Farooq Ansari has features for tracks fetched using Spotify's Web API, base on the tracks labeled hit or flop by the author, which can be used to make a classification model to predict whether any given track would be a 'Hit' or not. While the original Kaggle dataset was created by Ansari, the team created our own machine learning model to analyze the songs, and then further analyzed the data for a retrospective analysis of features for songs from each decade (1960s - 2010s)..

The original data, retrieved through Spotify's Web API (accesed though the Python library Spotipy), includes 40,000+ songs with release dates ranging from 1960-2019. Each track is identified by the track's name, the artist's name, and a unique resource identifier (uri) for the track.

The dataset includes measurements for the following features, defined and measured by Spotify for each track:

1. danceability
2. energy
3. key
4. loudness
5. mode
6. speechiness
7. acousticness
8. instrumentalness
9. liveness
10. valence
11. tempo
12. duration (in milliseconds)
13. time signature
14. target (a boolean variable describing if the track ever appeared on Billboard's Weekly Hot-100 list)

Two additional features were defined by Ansari and extracted from the data recieved by the API call for Audio Analysis of each particular track:

15. chorus hit (an estimation of when the chorus of the track would first appear, i.e. "hit")
16. sections (number of sections inside the song)

Details about each of the features and what they measure can be found on Kaggle, and through Spotify's documentation. Ansari's original source code can be found here.

The team trained and tested 4 different models to evaluate the dataset, in addition to variations within some of the models.

1. SVM (Support Vector Machine) Model
2. Logistic Regression
3. Neural Network/Deep Learning Model
4. Random Forest Model

Note: The models were run in local servers and the ones with the best results were run through Google's Collaboratory to maximize their score.

We ran an SVM model with all 16 features, in two different functions for the normalization: one with Standard Scaler and the other with MinMax Scaler, both for x values and with the following results:

from sklearn.svm import SVC 
model_SVM = SVC(kernel='linear')
model_SVM.fit(x_train_scaled, y_train)

• Standard Scaler:

Training Score: 0.7257776768626942
Testing Score: 0.7308553079692517

• MinMax Scaler:

Training Score: 0.7256479288981154
Testing Score: 0.7306606986474652

Same as SVM, we ran the model with all 16 features and with the same normalization variations:

from sklearn.linear_model import LogisticRegression
model_LR = LogisticRegression()
model_LR.fit(x_train_scaled, y_train)

• Standard Scaler:

Training Data Score: 0.7280158292516786
Testing Data Score: 0.7288119100904933

• MinMax Scaler:

Training Data Score: 0.7280482662428233
Testing Data Score: 0.7283253867860271

With further analysis of the data, we decided to normalize each feature independently and ran the same models to see if the results improved.

The features included in this process were:

• Loudness (also adjusted to positive values by adding 50)
• Duration (modified from microseconds to seconds)
• Key
• Tempo
• Time_signature
• Chorus_hit
• Sections

The results for each model were:

• SVM

Training Data Score: 0.765026436147783
Testing Data Score: 0.7634523693684927

• Logistic Regression

Training Data Score: 0.7280482662428233
Testing Data Score: 0.7286173007687068

None of these adjustments produced improvements high enough where it seemed worth it to develop the models further. Therefore, we decide to test other types of models altogether.

We originally designed the archetecture of our deep learning model to have 4 layers, while measuring the loss and accuracy levels during training and testing of the model. In the process of training and testing the model, we discovered that the addition of the final layer was essentially overtraining the model, leading to decreased accuracy. As such, we eliminated the last layer from the final version of the model. The best variation of the model was with 500 epochs, a batch size of 2000, and MinMax Scaler normalization.

#Create a sequential model with 3 hidden layers
from tensorflow.keras.models import Sequential
model = Sequential() 

from tensorflow.keras.layers import Dense
number_inputs = 15  
number_classes = 2

model.add(Dense(units=14,activation='relu', input_dim=number_inputs))
model.add(Dense(units=120,activation='relu'))
model.add(Dense(units=80,activation='relu'))
model.add(Dense(units=number_classes, activation='softmax')) 

#Compile the Model
import tensorflow as tf
opt = tf.keras.optimizers.Adam(learning_rate=0.001)
model.compile(optimizer=opt, loss='categorical_crossentropy', metrics=['accuracy'])

#Training the Model
history = model.fit(X_train_scaled, y_train_categorical, epochs=500, batch_size=2000, shuffle=True, verbose=2)

Training Score: 0.7969444394111633
Testing Score: 0.7762965559959412

The initial test of the Neural Network, with all 16 features, performed a bit better than the SVM or Logistic Regression Models. For this reason, we decided to run several variations to see if eliminating any one of the features, or some features in combination, would improve the model's accuracy. The results can be seen in the table below.

Overall, these tests showed that eliminating any features did not improve accuracy and the best results came from including all 16 features.

In this case, the best variation of the model was with Standard Scaler normalization. With this model, we were able to see immediately that no one feature seemed to have a particularly strong weight or influence on the overall results:

Individually, each feature was quite weak as a predictor of whether or not a song would be a hit. However, with all the features included, this was actually the best performing model.

from sklearn.ensemble import RandomForestClassifier
model = RandomForestClassifier(n_estimators=200, max_depth=25) 
model = model.fit(x_train_scaled, y_train)

Training Data Score: 0.9993836971682507
Testing Data Score: 0.7883623625571665

We saw that the adjustments we were making resulted in only slight improvements or variations in the results of each model. This led us to believe that any real improvement to the results required taking a closer look at the data we were using to train the model. We theorized that, since music tastes change relatively less from one decade to the next but are much more pronouced over 30-40 years, perhaps limiting the data to a block of twenty years would improve the accuracy. We decided to use the songs from the 2000s since that is the most recent period of 20 years, and thus might more accurately predict what would be considered a hit today. With these adjustments, the accuracy of the model did in fact improve. The final adjustments made to the model, which maximized the results, were number of trees (200), and the max depth (25).

Train score: 0.9967398391653989
Test score: 0.8464797913950456

After running the 4 models and the variations described above, we chose the Random Forest model with adjusted settings as the final model, given that it had produced the best results with the highest levels of accuracy.

We designed a public webpage for final publication of the machine learning model, deployed on Heroku.

Visitors to the site can input a recently released song (or their favorite past song) to see how the model would determine whether it might be a "hit" or not. A second page provides interactives graphs to analyze the preferences in different song features across all decades in the full dataset (1960s-2010s), and provides a bit more background as to how each feature is defined.

With graph analysis, we noticed consistency in some audio features for hits throughout the decades, meaning that hits have higher quantities of these features and they seems to retain the same influence as to whether a song is popular. These feature include: danceability, energy, loudness and valence. Other features have increasingly fluctuated in their importance from one decade to the next, characteristics like chorus hit, duration, liveness, mode, sections and speechiness. That is to say that maybe in the 60's these features were more prominent in hits of that era, but in recent decades songs with higher levels of these features are more likely to be flops.

• The original dataset was retrived from Kaggle and created by Farooq Ansari.
• The template for the website deploying the model was designed by HTML Codex
• Graphics were generated through Tableau
• The first image above was retrive from Luxemburg Times site on 06/23/2020.