Communicating Data with Tableau

Preface

There is a huge opportunity to find and share the insights contained in data. This is not a new development. People from Florence Nightingale to William Playfair to Dr. John Snow and countless others have been changing the world with data for centuries.

The challenges we face today are different, and so are the tools at our disposal. But just as back then, the person who would perfect the art of communicating data in our time must be at once analytical, articulate, and creative. That is to say: the result, when done well, often involves a combination of numbers, words, and images.

More than anything, however, empathy is required. The person doing the communicating must understand the members of the audience: what will make sense to them, what motivates them, and what concerns them. The inherent challenge and the resulting satisfaction of making a meaningful impact with data are what draw me to this endeavor more than anything else.

Tableau Software has developed and created a visualization querying engine and user interface that make it easy to discover and communicate with data. Once you get the hang of it, it can be a real pleasure to use. Tableau makes it possible to quickly view data from a number of different angles, to combine it with additional data sets and conduct a more sophisticated analysis, and to craft a message that will really hit home.

But to fully unlock the power of Tableau, the communicator of data needs to appreciate what will work well in each particular situation. The software is designed to steer the user down the straight and narrow pathway of best practices, but it is up to the user to know when to adhere to rules of thumb, and when to break them. Also, there are many options to choose from, and many decisions to make when crafting a message. It’s important to understand the range of alternatives, how to use each one well, and which to employ.

In my current role as Tableau Public Product Manager at Tableau, I have the privilege of interacting with a host of talented individuals who are setting data free from the confines of spreadsheets and tables and making it easy to see what the data shows about our world. On my own blog, I have been attempting to do the same thing for the past three years, and after dozens of projects and experiments, I have learned a number of techniques that work well, and some that don’t work so well.

In this book, I have attempted to provide advice to the would-be communicators of data, to guide them in the proper usage of Tableau to achieve the desired effect. My hope is that this book will help others learn what I have learned, and avoid the mistakes I wasn’t wise enough to dodge the first time around.

Intended Audience

This book is for anyone who has data and who wants to use it to learn something about their world, which they can then share with others around them. More particularly, it’s for people who are brand new to Tableau, or who have been using it for a while but are looking to improve the outcome of their communication efforts. That applies to analysts and managers in corporations, journalists within media organizations, leaders of nonprofits, researchers, teachers, and anyone else who is passionate about a subject for which data is available.

Tableau is a software tool for programmers and nonprogrammers alike. It does not require knowledge of any computer programming languages as a prerequisite, but a basic familiarity with data types, spreadsheets, and statistics is necessary. The examples used throughout the book can be re-created by connecting to Excel spreadsheets that are available for download on http://dataremixed.com/books/cdwt. While Tableau Desktop allows users to connect to data in a wide variety of databases, cloud sources, and Hadoop technologies, the goal is to provide material that anyone can follow along with.

Although even experts can learn from others, I haven’t particularly geared this book toward the guru-level Tableau user. Furthermore, it’s not intended to be an exhaustive manual that covers every function and feature in the software.

At the time of writing of the first version of this book, Tableau Desktop 8.1 and Tableau Public 8.1 are available for purchase and download, respectively. A free trial version of Tableau Desktop 8.1 can also be downloaded and installed. Tableau is currently available for Windows only.

Assumptions This Book Makes

This book assumes that the reader has data and that it’s ready to use. Example files are available in a formatted and cleaned state, but this book will not cover all of the steps necessary to get a data set into this state. While these data wrangling tasks often account for much of the time and effort involved in any project, they go beyond the scope of what’s covered in this book.

This book further assumes that the reader has access to Tableau Desktop 8.1 or Tableau Public 8.1, which is currently only available to install on Windows.

Contents of This Book

Chapter 1, Communicating Data, discusses the basic process of encoding a data-driven message into a signal and transmitting (presenting) it to receivers (audience members), who then decode it and take some action based on their understanding of the message.

Chapter 2, Introduction to Tableau, deals with the different software products that Tableau offers, as well as the basics of the Tableau user interface.

Chapter 3, How Much and How Many, teaches how to communicate a single group of absolute numerical quantities in the form of measurements (how much) and counts (how many).

Chapter 4, Ratios and Rates, covers normalized comparisons of a single group of quotients that either have the same units (ratios) or different units (rates). Calculated fields and ranks are introduced, and a simple data blending example is included.

Chapter 5, Proportions and Percentages, covers another kind of normalized comparison: part-to-whole relationships per unit and per one hundred. We’ll introduce Quick Filters, Table Calcs, and reference lines in this chapter.

Chapter 6, Mean and Median, deals with the important topic of measures of central tendency, featuring the new box-and-whisker plot chart type, as well as the oft-used dual-axis chart.

Chapter 7, Variation and Uncertainty, addresses a challenging but important topic by showing readers how to give an accurate and honest view of the real world, instead of painting an overly simplistic picture.

Chapter 8, Multiple Quantities, takes the analysis to a new dimension by considering how to effectively communicate more than one variable at a time. Scatterplots, tooltips, and trend lines feature prominently in this chapter.

Chapter 9, Changes Over Time, tackles a critical element of every data visualization: time. Simple methods like line plots are included as well as more advanced chart types like connected scatterplots, Gantt bar charts, and slopegraphs.

Chapter 10, Maps and Location, walks the reader through the fundamental concepts of visualizing geospatial data by creating both circle maps and filled maps.

Chapter 11, Advanced Maps, covers more sophisticated map types such as shape maps, maps with paths, custom background images, and mapping shape files on axes.

Chapter 12, The Joy of Dashboards, is a tour of different styles of dashboards: explanatory, exploratory, storytelling, and infographics. This chapter gives a sense of the different ways people combine multiple charts and objects into a single view.

Chapter 13, Building Dashboards, shows readers how to employ an eight-step process to build richly interactive dashboards in Tableau.

Chapter 14, Advanced Dashboard Features, gives readers a sense of how dashboards can be enhanced with web pages, tabs, navigation affordances, and animation.

Conventions Used in This Book

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Constant width

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Constant width bold

Shows commands or other text that should be typed literally by the user.

Constant width italic

Shows text that should be replaced with user-supplied values.

Note

This element signifies a tip, suggestion, or general note.

Warning

This element indicates a warning or caution.

Using Code Examples

Supplemental material (examples, exercises, etc.) is available for download at http://dataremixed.com/books/cdwt.

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Acknowledgments

I’d like to thank the founders and developers of Tableau Software for making the product that makes this book possible, and for being bold enough to make such a highly functional version of the product, Tableau Public, entirely free. I wouldn’t have gotten started without it.

I’d like to thank O’Reilly Media for agreeing to work with this first-time author, and my editor, Julie Steele, for helping me navigate what turned out to be a much more challenging and time-consuming endeavor than I expected.

I’d also like to thank all the people who have taught me what I know over the years: the gracious and welcoming community of data visualization enthusiasts and professionals like Andy Kirk, Alberto Cairo, and Santiago Ortiz; the incredibly talented community of Tableau Public authors like Joe Mako, Andy Kriebel, Peter Gilks, Jonathan Drummey, Ramon Martinez, Kelly Martin, Anya A’Hearn, Robb Tufts, Ryan Sleeper, and countless others; and my colleagues within Tableau who share my passion for data, like Ellie Fields, Andy Cotgreave, Mike Klaczynski, Jewel Loree, Daniel Hom, and Dustin Smith, to name just a few.

Lastly, and most importantly, I’d like to thank my wife, Sarah, and our two wonderful sons, Aaron and Simon, who supported me in so many ways throughout the writing of this book, which was also our first year in the Seattle area. You three mean everything to me.

Sarah, I dedicate this book to you.