Data Viz Approach and Data Storytelling
When looking at this dataset, most people's first approach would be a choropleth map, coloring the source countries by the number of individuals naturalized from that country. That's a pretty simple approach, but when a huge part of the map would be uncolored (the United States), and the range of naturalizations by year is very spread out, I didn't think it was an effective approach to tell this datastory. I noticed that for 2017, 66% of the naturalizations for that year came from the top 20 countries. Instead of trying to squeeze data for more than 202 countries into a single viz, I decided to focus on these top 20.
Specifically, I wanted to look at the change of the nations that make up the top 20 over time. To accomplish this, I decided to employ a Sankey Bump Chart, showing the rank by year with smooth, aesthetically pleasing lines. I modified a data densification approach that Marc Rueter of Tableau presented at the 2017 Tableau Conference. Specifically, I modified the technique to use dual axes. The first drives the data densification and smooth lines with a parameterized Bin on year, and the second looks at just the year and displays a circle where the smooth line crosses the year. I did this because the smooth, curved line can distort the viewer's perception of where the year falls, and with my aversion to grid lines, the circle pulls the viewer's eye to the specific point. Additionally, I used this second axis to drive my tooltip so that it only showed at the year.
Even with only the top 20 countries, the viz is effective at showing the big players in providing new citizens to the United States. However, this is far from the only effective viz type. I can't wait to see how the Tableau Community approaches this dataset. Download the data and see what makes the most sense to you. Create your viz and post your work to Tableau Public and Twitter with the hashtag #ThrowbackDataThursday, tagging @TThrowbackThurs. We'd really love to see what you can come up with!
This week's dataset comes from Department of Homeland Security. Please be sure to cite the source on your viz.