The Hammock Plot: Where Categorical and Numerical Data Relax Together

TL;DR

The paper introduces the hammock plot, a visualization method combining categorical and numerical data, along with a Stata implementation and diverse examples, including a new dataset on the 2020 Tour de France.

Contribution

It presents the hammock plot as a novel visualization technique and provides a practical implementation in Stata, expanding tools for multivariable data analysis.

Findings

Demonstrates highlighting and missing value visualization

Shows axes can be on the same scale for comparison

Includes a new dataset on the 2020 Tour de France

Abstract

Effective methods for visualizing data involving multiple variables, including categorical ones, are limited. The hammock plot (Schonlau 2003) visualizes both categorical and numerical variables using parallel coordinates. We introduce the Stata implementation hammock. We give numerous examples that explore highlighting, missing values, putting axes on the same scale, and tracing an observation across variables. Further, we discuss parallel univariate plots as an edge case of hammock plots. We also present and make publicly available a new dataset on the 2020 Tour de France.