The following is an excerpt from the book Security Metrics:
Replacing Fear, Uncertainty, and Doubt.
In this section of
Chapter 6:
Visualization (.pdf), author Andrew Jaquith explains how
security professionals can present their hard-won data in a clean
and elegant manner.
@39115
JUST SAY NO TO THREE-DIMENSIONAL GRAPHICS AND CUTESY CHART
JUNK
I have never understood the fascination with three-dimensional pie
and bar charts. I am continually astounded at how otherwise
respectable security software companies insist on shipping
reporting modules that sport ridiculous, gratuitous 3-D graphics.
Unless your professional duties include preparing exhibits for the
Department of Energy's nuclear weapons simulation program, few
conceivable data sets genuinely merit a 3-D exhibit. Simple, clean,
"flat" charts make the same points a faux 3-D chart does, but with
less ink. Certainly, ordinary bar charts and pie charts do not
require them; the artificial depth only distracts the viewer from
the data.
Recent versions of Microsoft's ubiquitous Excel spreadsheet
software allow users to add photographs and flashy wallpapers to
the backgrounds of charts or to the colored portions of area
charts. Avoid these unless the exhibit serves some theatrical
purpose. For example, a flashy photo background might feel right at
home as part of a sales-oriented slide deck containing scads of
music and the obligatory slide transitions. Nobody will take the
exhibit seriously anyway, so the extra flash will not matter. But
for situations in which the presenter intends to inform, persuade,
or present results of analyses, charts should use white or
translucent backgrounds and should omit 3-D.
DON'T GO OFF TO MEET THE WIZARD
Thanks to the profusion of "wizards," "assistants," talking paper
clips, and other assorted digital menservants, modern desktop
applications have made it easier than ever to create incredibly
busy and tasteless graphics. It is helpful that Excel's wizards
speed users through the process of selecting data series, titling
charts, and labeling axes. However, the results disgorged at the
end are, at best, overeager. Even the humblest line chart is
festooned with a Technicolor palette, distracting axis tick marks,
unnecessary grid lines, and a drab gray background. All these
aspects distract the reader from the data.
An additional downside is that Excel's default layout wizards
produce a particular, immediately recognizable style, one that
screams "amateur"! (For me, spotting Excel punters is an admittedly
snobbish, and slightly guilty, pleasure.) Use digital menservants
carefully, and only as a starting point for exhibits. Generally
speaking, graphics created for all but the most casual personal
uses require cleanup.
ERASE, ERASE, ERASE
Most charts produced by desktop software default settings contain a
profusion of superfluous ticks, grid lines, plot frames, and chart
frames. There is a good reason why most mainstream business
publications use them sparingly: they look clumsy, and they
distract attention from the data. You can eliminate all these
ornaments without losing any meaning. In fact, your chart will look
cleaner as a result.
@39056The general rule: if you do not need it, erase it. Start
getting into the habit of eliminating the tick marks immediately
after creating a chart. Generally this involves formatting the axes
with "No major tick marks" and "No minor tick marks." Likewise,
eliminate the plot frame and chart frame by formatting each with
"No border." These are not needed; the axis lines provide all the
framing the chart needs. For bar charts, eliminate the enclosing
borders for the bars; the bars themselves provide all the
information needed. Grid lines are trickier. Although I usually
erase them, they do have appropriate uses.
For sparse exhibits in which subtle comparisons are neither
possible nor desirable, omitting the grid eliminates visual noise
without sacrificing readability. For dense exhibits containing
large data series, however,muted grid lines help readers compare
individual data points.When using grid lines, always draw them in a
light color (20 to 25% gray) or in black as sparse dots. They
should not intrude on the data and should sit in the
background.
In fact, other than those required to plot the data, good charts
contain no lines other than the x- and y-axes, and (perhaps) some
muted grid lines. Even the axis lines can be muted further: try
choosing a thin line (1-point) and softer color (50% gray). The
cumulative effect of these erasures results in a crisp chart with
few distracting lines. Although my recommendations may seem
Spartan—severe, even—the results are worth it.
RECONSIDER TECHNICOLOR
Make no mistake—when used judiciously and appropriately, color can
add tremendous depth and richness to charts and graphs. The eye's
ability to make sense of, and discern between, wide ranges of
colors is one of the great wonders of the human physiognomy. It is
what enables us to discern objects in our peripheral vision or spot
a blazer-wearing deer hunter from a long distance.
@39058Tufte has previously noted that small, saturated spots of
color are often the best way to draw attention to key points or to
outliers in data sets. By that rationale, it stands to reason that
many large swatches of saturated color are almost certainly
overwhelming to the human eye.
In that light, the default Technicolor palette for Excel charts
is less than ideal; the colors are far too saturated for most uses.
The default palette includes Lemon Pledge Yellow, Kermit the Frog
Green, Ticket-Me-First Red, and Cobalt Blue. For charts with
multiple data series, that is quite an eyesore.
To prevent your exhibits from looking like an irradiated piece
of luggage as it goes through an airport metal detector, consider
these two suggestions:
- Mute the color palette. Reds, blues, greens—beautiful colors,
all. But they need not saturate the screen. Consider replacing red
with burgundy, blue with navy, and "Kermit" green with hunter or
forest green. Readers will thank you for it; their eyes will relax
rather than twitch. That said, if you need to emphasize a
particular data point or series, use a small, focused swatch of
saturated color.
- Use a monochromatic palette. An alternative to a less saturated
palette is one that uses only black, white, and shades of
gray.Monochromatic palettes work well when the target output device
cannot be guaranteed, and when the number of data series is about
five or less. A reasonable monochromatic palette includes white
(with a black border), 20/25% gray, 50% gray, 75% gray, and black.
Use pure colors; avoid fill patterns because they tend to
"vibrate." On a related note, because photocopies of good exhibits
(like the ones you will produce after reading this book!) tend to
proliferate mysteriously into unforeseen hands, get into the habit
of printing all exhibits in black and white first, before
finalizing designs. By "proofing" exhibits this way, you can catch
potential reproduction problems before they become an
issue.
While I'm on the subject of color, be careful with yellow. There
is nothing intrinsically wrong with yellow, but it tends to wash
out in printed work and presentations. Use it as a "highlighter
pen" accent color, but not as a data series color unless the
background is very dark.
Learn more ways to enhance your presentations. Download the
rest of
Chapter 6: Visualization (.pdf).
Reproduced from the book Security Metrics: Replacing Fear,
Uncertainty, and Doubt Copyrightã [2007], Addison Wesley
Professional. Reproduced by permission of Pearson Education, Inc.,
800 East 96th Street, Indianapolis, IN 46240.Written permission
from Pearson Education, Inc. is required for all other
users.