Florida is the south easternmost U.S. state, with the Atlantic on one side and the Gulf of Mexico on the other. Florida is a famous tourist destination. In 2016 alone, approximately 113 million tourists visited Florida. With Tourists and happening night life, unfortunately crime (involving gun) is high.
Florida’s self-defense law (The stand your ground) was passed in 2005 states –
“A person who is not engaged in an unlawful activity and who is attacked in any other place where he or she has a right to be has no duty to retreat and has the right to stand his or her ground and meet force with force, including deadly force if he or she reasonably believes it is necessary to do so to prevent death or great bodily harm to himself or herself or another or to prevent the commission of a forcible felony.”
After this law has been passed, there is an increase in gun deaths. However I saw a visualization which gives completely opposite visual representation of this fact.
The following visualization depicts the gun deaths in Florida from 1990 to 2010 (Note the Gun law is passed in 2005 as marked in diagram)
What I liked about the diagram
1] Simple and eye catchy diagram – It does not try to integrate lot of unnecessary information. Also “Red” color attracts the viewers. It can also be associated with “blood” and hence human life loss
What I did not like about the diagram
1] Inverted Y axis/ Wrong first impression – Upon careful observation, I noticed that the Y axis is inverted. This means 0 starts at top and large numbers are at bottom. I did not understand the use of this inverted logic. This creates confusion and user can wrongly interpret that – gun deaths have significantly reduced after 2005 (After “Stand your ground”). This is because of human pre assumption of reading/interpreting line graphs is fixed
2] No units mentioned for Y axis – What are these numbers. Are they in hundreds or thousands. The core principles of visualization of “Scales” is not followed.
3] Time series fails to deliver the message – Here the years (along the X axis) have been grouped in 10 years bracket. However since this graph shows the time series, every year’s information is important. This only shows a general trend over years but fails to convey accurate figures.
A different version of above visualization using standard/normal Y-axis
The above visualization shows us how drastically the slope/trend can change if we invert/change the Y axis. Now the viewer can get clear picture than gun crimes have increased after the law is passed in 2005
How will I change this visualization –
1] Compare Florida with rest of USA – As seen in the below diagram, I would compare the gun crime in Florida with rest of USA. The units are well defined and user can clearly understand the increase in gun crime after 2005
2] Set the context to 2005 – A vertical line clearly indicate the time when Gun law was passed.
3] Use of color – I will use red color for Florida and blue color for rest of USA. This clearly shows the difference to the user
4] Standard Y axis – It is better to use the standard assumptions, and not try to make simple things complicated. This will be easy for users to quickly and clearly understand the trend
Learnings from the class –
1] Define the context – The visualization becomes more meaningful if context is clear and well defined
2] This example is a great reminder that we bring our own assumptions to our reading of any illustration of data. Something which goes up is increase in value and something which comes down is decrease.
3] Not to overcomplicate things – It is good to be artistic. But if we overcomplicate things, then user may interpret the visualization in a wrong way
4] Choose your Y-axis intelligently – This can make your visualization look completely different/deceptive.
5] Identify your audience – Not all of your audience will be mathematicians. Most of them will only look at the figure and try to identify the trend (without going into details)
References – http://www.businessinsider.com/gun-deaths-in-florida-increased-with-stand-your-ground-2014-2
http://www.orlandosentinel.com/travel/os-bz-visit-florida-tourism-2016-story.html
http://stat.pugetsound.edu/courses/class13/dataVisualization.pdf