always keep in mind…• arrangement
• emphasis
• contrast
• repetition
• alignment
• proximity
anatomy of a chart
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Axes
axis x(value axis)
axis y (category axis)
Data Points
Trend Lines or Plots
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Labels
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Title
Weather Data for Cambridge, MA (source: Weather.com)
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font size in axis labels is too small for a
presentation
crossing ticks in
corners are distracting
(“chartjunk”)
overlap of label with
lines causes an info jumble
Clutter
represent complex data in columns and rowsor as an underlying grid to arrange information
tables
show pieces of a whole; represent percentages
Figure 2: Leading Causes of Death for Youth and Adults (2003)
pie charts
used to represent one data groupsimple bar charts
used to represent more than one data group complex bar charts
used to plot interval dataline graphs
used to plot data pointsscatter plots
organizational chartsused to reflect/show hierarchy
follow spatial contours; used to geographically/spatially represent data
data maps
data represented by picturespictograms or pictographs
bad, bad data displays
• labels are almost impossible to read
• arrangement of information makes no sense
• just because you can does not mean you should…
• 3D effects and arrangement completely obscure information
• flattened text is difficult to read and associate with the data
• pie charts are used to show percentages, but there are no percentages here
• size of pies makes it difficult to interpret data
• what’s the point? what is this telling us?
• if this chart is supposed to reveal trends in overall consumption, a pie chart should be used to reveal percentages
• if this chart is supposed to compare consumption across the week, a bar chart would work best
• if this chart is supposed to reveal trends in overall consumption, a pie chart should be used to reveal percentages
• if this chart is supposed to compare consumption across the week, a bar chart would work best
• different types of plot lines (i.e., black line and red line) not explained
• equations clutter the chart
• is “Surveyor vs. RIPE” the title of the chart? if so, it should be in a different font face and size from the axis labels > there’s no contrast here to cue us in
• bar chart is absolutely unnecessary
• scale is too large for data displayed
• too much data!
how to lie with data displays
large scales hide changes
drastic scalingemphases changes
level of detail can obscureor reveal important information
good, descriptive labels are crucialto reveal meaning and purpose
certain formatting options canvisually overemphasize information
1. launch Microsoft Word
2. in a new document, select Insert Picture Chart
creating data displays
a few thoughts for data displays…
• This often takes longer than you think it will—be sure to give yourself the time you’ll need to work on them
• Refer back to this PowerPoint to make sure you’re using the correct display for your data
• make sure to title and label your data displays appropriately (Word, Excel, and whatever other applications you use might provide some template/help with this, but you might have to access deeper features to add labels not default-offered by the application)
• Your data displays are due with your rough draft