Our nation's gun debate has been thrust back into the spotlight, and as a data scientist I am interested in what data we have and how we can visualize it to glean new information and knowledge. As we know, data visualization is an art as well as a science, so when we see a data visualization we are seeing the writer's perspective of the data. What can we track? Murder rates, laws, friend connections, gun sales, registrations, campaign donations, and crimes to name a few. Will visualizing this data highlight core issues and help us understand what we can do, or what we shouldn't do? Are writers' representations of data obscuring other insights? Are writers primarily attempting to appeal to our heartbreak over gun violence tragedies? Some visualizations empathize with the human loss in gun violence, other infographics and interactive visualizations look to shed light on gun data; "NRA influence," "officers down," and "guns across state lines" are signature works of the Washington Post. The message of "guns across state lines" is stated plainly across the top as "... states with strong gun laws import from states with weaker laws." The static presentation of the data certainly highlights this fact, using the classic red=bad, green=good, implying that good states are receiving guns from bad states. Viewing the data dynamically by selecting different states and observing where guns are coming from and going to, highlights the proximity factor in gun import/export; a State's physical proximity is also important.
What is the effect of the law on gun movement? New York's has very strict guns laws compared to the rest of the country, and its primary gun suppliers are VA, GA, and FL, which all have almost no gun laws by comparison; this trend is also true of Illinois. By itself this would confirm the hypothesis, however we can find a similar trend among states with very few regulations, and by contrast California supplies guns throughout the country and especially to neighboring states. We can more easily break apart the gun export/import at Trace the Guns, which shows that many states have significant amounts of both.
One thing is clear, states with more strict laws export less compared to their imports; perhaps it's easier to control supply than demand. Based strictly on this data, if the goal is to limit availability of guns for violent crimes, either all states would have to adapt strict gun laws, or interstate gun sales would have to stop. I believe we need better data, or we need to recognize different trends.