9 Tabular Modeling Deep Dive
Tabular modeling takes data in the form of a table (like a spreadsheet or CSV). The objective is to predict the value in one column based on the values in the other columns. In this chapter we will not only look at deep learning but also more general machine learning techniques like random forests, as they can give better results depending on your problem.
We will look at how we should preprocess and clean the data as well as how to interpret the result of our models after training, but first, we will see how we can feed columns that contain categories into a model that expects numbers by using embeddings.
9.1 Categorical Embeddings
In tabular data some columns may contain numerical data, like “age,” while others contain string values, like “sex.” The numerical data can be directly fed to the model (with some optional preprocessing), but the other columns need to be converted to numbers. Since the values in those correspond to different categories, we often call this type of variables categorical variables. The first type are called continuous variables.
jargon: Continuous and Categorical Variables: Continuous variables are numerical data, such as “age,” that can be directly fed to the model, since you can add and multiply them directly. Categorical variables contain a number of discrete levels, such as “movie ID,” for which addition and multiplication don’t have meaning (even if they’re stored as numbers).
At the end of 2015, the Rossmann sales competition ran on Kaggle. Competitors were given a wide range of information about various stores in Germany, and were tasked with trying to predict sales on a number of days. The goal was to help the company to manage stock properly and be able to satisfy demand without holding unnecessary inventory. The official training set provided a lot of information about the stores. It was also permitted for competitors to use additional data, as long as that data was made public and available to all participants.
This is just a preview of this chapter. The rest of this chapter is not available here, but you read the source notebook which has the same content (but with less nice formatting).