Sunday, June 23, 2013

Energy Pareto Info-graphic

This entry discusses a data graphing experiment.  If you want to learn about global energy use, the other entry is a much better place to start! Think of this chart as an executive summary. Supporting information is in the other entry.

A Pareto Analysis is usually done with a series of bar graphs, always choosing the biggest bar, or largest contributing category. By working through a sequence of graphs, people find the category that provides the greatest traction on improvement (on a percent improvement basis).

Sometimes focus areas are highly refined.  People have been working on improving them a long time so it is difficult to obtain a percentage of improvement.

Back to the graph.  The sequence of bar graphs method sometimes loses context on the original goal. This stacked column graph replaces an entire bar graph with a single column. We also bring the determined largest traction category back across as the foundation of every stacked column in the analysis. It is there for a context comparison every step of the way.



The graph shown below is an area graph.  It is kind of like a pie chart and a donut chart combined. Some will recognize it as a Venn diagram with more detail than is normally presented. The energy used is represented by the area covered by any given color. The largest consumer of energy is drawn as a circle in the middle of a donut displaying the less prominent consumers. 

This method lets one recursively apply the method until the final action based information is presented as a pie chart. People can process the action implications of a pie chart a little bit faster. Also, the dimensional discipline changes a little bit inside the pie chart.  The size (area) of the pie is correct: It represents the energy used by light vehicles on workday commutes. But inside the pie we don't know how many ride together in the carpools, or how long their commutes are. We do know that 88% drive alone, and if all drove in pairs, or many in triples, we could use approximatey half as much energy for workday commutes.

The savings obtained by reducing the area of the "Drove Alone" category by half are clear. Traveling with more in each car on the way to, and from, work will make a real difference, even when viewed in context of the U.S. energy consumption of all sectors - that would be the large yellow circle that represents 71.3 Quads. 

This radial area graph can be misinterpreted. Please treat as an experimental footnote.



Feedback on the combination graph indicated that people do not always weigh area properly and might use radius, or diameter,  as a proxy for area.  This would be a mistake by the reader, but as the publisher there is some accountability for proper interpretations. Please use the column graph. It is less prone to mistakes.  

The radial area graph can be misinterpreted. Please treat as an experimental footnote. 


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