Tidy Modeling with R: A Framework for Modeling in the Tidyverse

Book Preface

Welcome to Tidy Modeling with R! This book is a guide to using a collection of software in the R programming language for model building called tidymodels, and it has two main goals:

First and foremost, this book provides a practical introduction to how to use these specific R packages to create models. We focus on a dialect of R called the tidyverse that is designed with a consistent, human-centered philosophy and demonstrate how the tidyverse and the tidymodels packages can be used to produce high quality statistical and machine learning models.
Second, this book will show you how to develop good methodology and statistical practices. Whenever possible, our software, documentation, and other materials attempt to prevent common pitfalls.

In Chapter 1, we outline a taxonomy for models and highlight what good software for modeling is like. The ideas and syntax of the tidyverse, which we introduce (or review) in Chapter 2, are the basis for the tidymodels approach to these challenges of methodology and practice. Chapter 3 provides a quick tour of conventional base R modeling functions and summarizes the unmet needs in that area.
After that, this book is separated into parts, starting with the basics of modeling with tidy data principles. Chapters 4–9 introduce an example data set on house prices and demonstrate how to use the fundamental tidymodels packages: recipes, parsnip, workflows, yardstick, and others.
The next part of the book moves forward with more details on the process of creating an effective model. Chapters 10–15 focus on creating good estimates of performance as well as tuning model hyperparameters.

Finally, the last section of this book, Chapters 16–21 cover other important topics for model building. We discuss more advanced feature engineering approaches like dimensionality reduction and encoding high-cardinality predictors, as well as how to answer questions about why a model makes certain predictions and when to trust your model predictions.
We do not assume that readers have extensive experience in model building and statistics. Some statistical knowledge is required, such as random sampling, variance, correlation, basic linear regression, and other topics that are usually found in a basic undergraduate statistics or data analysis course. We do assume that the reader is at least slightly familiar with dplyr, ggplot2,
and the %>% “pipe” operator in R, and is interested in applying these tools
to modeling. For users who don’t yet have this background R knowledge, we recommend books such as R for Data Science by Wickham and Grolemund (2016). Investigating and analyzing data is an important part of any model process.
This book is not intended to be a comprehensive reference on modeling techniques; we suggest other resources to learn more about the statistical methods themselves. For general background on the most common type of model, the linear model, we suggest Fox (2008). For predictive models, Kuhn and Johnson (2013) and Kuhn and Johnson (2020) are good resources. For machine learning methods, Goodfellow, Bengio, and Courville (2016) is an excellent (but formal) source of information. In some cases, we do describe the models we use in some detail, but in a way that is less mathematical, and hopefully more intuitive.