Fix That Graph: Real and Personal Property


I sometimes just shake my head when I see the visuals that are used in city and school district presentations.  The good news is that just about any data graphic can be improved and I’ve got ideas about how to do that.  This is the first in a series of posts to encourage the use of high-quality graphics in public presentations.

This graph was used in a presentation for a City Council.  Let’s take a look at the graphic to see what can be improved.

  1. Make the title say what the graph really shows.  Does this graph represent real and personal property tax percentages over the years?  What city is represented here?  The title doesn’t tell – so neither can you.  Write a specific title that tells what the data shows.
  2. Watch the choice of dates.  The choice of years at the bottom of the graph are interesting.  This makes it appear that there has been a consistent pattern in the years between 1999 and 2008, but is that in fact the case?  In terms of dealing with real estate assesments, it is CRITICAL to know the prior year’s assessments and patterns, because those are used for the upcoming year’s assessments.
  3. Use correct scales.  What is the highest possible number on the left scale?  One hundred percent?  I recommend using a scale that actually goes to 100% if that indeed is the top of the overall scale.
  4. Give meaning to the data.  For this particular piece of data, which is better?  An increase in the percentages or a decrease in the percentages?
  5. Explain the content.  What is the difference between real property and personal property?  Will most of the citizens who read this graph know that? 
  6. Explain, specifically, what the percentages mean.  In 2008, what does 6.21% for real property really mean?  Using a percentage tells us that it is 6.21% of something, but what is it?  We don’t know unless you tell us.
  7. Provide statements to go with the graph.  Don’t forget to provide an analysis of the information through bulleted lists or numbered statements.  You could also write a short paragraph.  You are communicating information to citizens – don’t be shy about what you want them to get from the graph.  Citizens will also make their own interpretations as well.
  8. Use a background color that is visually appealing and prints well.  Gray is not a terrific color with navy blue and dark green bars on the graph.  A simple white background would be better.  When you choose a background, choose one that looks good with the colors you are using and also prints well in color and black and white.

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