It’s hard to believe that I started this blog on August 13, 2009, 800 days ago (yes, I know my first post wasn’t until Aug 17).  The time has absolutely flow by and I’ve learned so much. 

For example, I’ve never shaded an axis in lieu of a color legend until today.  Heck, I never even thought about until I saw a bunch of vizzes on Tableau Public that were using this style. I’ve always included the color legends, but it’s really not necessary on a dual-axis chart like this with only two colors.  You might even call the use of a color legend chart junk in this case.

From what this viz tells me, I should stick to some specific topics if I want to drive traffic:

1. Sex
2. Politics
3. Cheating
4. Disasters

Does that surprise you?  It doesn’t surprise me since those are topics that generally dominate the news.

One final stat of interest: 90% of the total traffic to my blog has occurred since I posted this viz as part of the Flowing Data contest about STDs.  Nathan must be a pretty popular dude.

The news cycle has been focused on weather disasters lately, particularly tornados.  Thanks to the Guardian (get the data here) we can now “see” the trouble.  The data covers 1959-2010.  It’d be nice to have 2011 YTD in the dataset as well since there seem to have been so many tornados.

There are many options with which to filter on the right and if you want to see the list of disasters for a state or county, simply click on the bubble.

There are some really cool cuts of the data:

• Filter by hurricanes; the gulf coast lights up!
• I didn’t know North Dakota, Minnesota and Iowa had so many floods
• Avoid any states along the Mississippi River if you don’t like tornados (and Georgia too)
• Georgia has had the most recorded tornados since 1959…that both surprises and scares me, especially since they’re in North Georgia
• There have been more earthquakes in Washington state than California.  Who would have thought that?
• 9/11 is categorized as a Terrorist attack in Virginia, yet it’s listed as a Fire in New York.  Data cleanliness at its finest!

Do you see anything else interesting?  There is so much to explore.

I was watching a presentation/webinar today and the author was reviewing growth rates across time periods. Very straight forward data, quite easy to understand, yet the message was deceiving.

My mind immediately went back to Stephen Few's critique of the way BP was praising its efforts collecting oil from the disaster they themselves caused. In this case, BP was using a cumulative bar chart, which intentionally gave viewers the false impression that containment efforts were improving. Stephen quickly pointed out this fault and presented the data as individual measurements so that you could see the real story.

Back to the session I was attending. A chart was displayed that showed growth rates across time, but as individual points. The growth rate was measured from the previous point, not from the beginning of time. This leads you to believe that a negative growth that is less negative than the last point is actually improving results, yet in fact, the situation is just getting worse.

Think of this as the inverse of the problem Stephen addressed with BP.

I took some data for automotive sales in the United States to demonstrate what I mean. The blue line respresents the growth rate from one point to the next.

A good example to consider is October to December 2008. November experienced negative growth compared to October, but it's less negative than October, so the line goes up, giving you the impression the situation is improving. December is negative compared to November, but the line continues to go up because December is less negative than November.



I feel that a more proper way to tell the story is to use a cumulative line chart. The cumulative view is represented by the orange line. Consider the same time period. From a cumulative perspective, since November is negative compared to October, the line continues to decline. November's negative value has been added to October's negative value. The same situation continues in December.

Now, look at the different stories these lines tell. The blue line indicates you are only experiencing a 1% decline, yet the orange line says you've declined close to 50%.

Believe me, I know both lines are "correct." The point I'm trying to make is that you need to be sure to indicate the point you are measuring against. Very often sales figures are stated as "versus last year," but versus last year could mean many things.

In any event, September 2009 was a terrible month for the industry.

Try this to give yourself some real perspective. Courtesy of FlowingData. Try it yourself here.