

How to Lie with Data Visualization - matm
http://data.heapanalytics.com/how-to-lie-with-data-visualization/

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j2kun
It's interesting to see the y-axis scaling example, because the author uses it
to sell as incomplete a truth as the document he's criticizing.

> displaying the data with a zero-baseline y-axis tells a more accurate
> picture, where interest rates are staying static.

This is not true of all data, or even interest rates. Who's to say that a 0.01
increase in interest rate _doesn 't_ translate to large differences in money?
If this is true (and it depends a lot on the intended audience for the chart),
then representing it with a zero baseline is far more deceptive and the "bad"
chart does a better job showing that the small increases are in fact getting
steadily bigger.

The problem is that data alone is not sufficient to say anything, and the
context (in this case, noise in interest rate changes) is too important to
give a single rule for your scale. How you interpret context, of course,
depends on what you're selling.

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aperrien
It can also depend on what is the easiest thing for you to hear. Take a look
at this article: [http://blogs.reuters.com/great-debate/2014/04/14/america-
the...](http://blogs.reuters.com/great-debate/2014/04/14/america-the-
anecdotal-nation/)

It's disturbing how much we look to confirm out preset biases.

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Mithaldu
The last example is especially striking to me, as i've seen that graph used in
a discussion about the effects of gun laws. The person posting it had taken
the time to remove the numbers.

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notahacker
I was going to say it was the most heinous deliberate visual distortion of
data to create the wrong impression I'd ever seen, and then I read the BI
article that was clearly slanted _the opposite way_ from the apparent bias in
the graph, and noted that they claimed the graph was originally from Reuters,
an organization relatively unlikely to sacrifice their credibility on the
altar of defending Florida's "stand your ground" laws. If people _choosing_
the visualizations didn't read too much into the message they conveyed, what
does that say about the average reader taking a quick glance ?

If I were to chart _people that interpret visualizations to draw conclusions
the narrative doesn 't always express_ and _people that see visualizations as
a pretty picture to go with what the words say_ , I have a feeling the former
group would be so small I could get away with using a pie chart[1]

[1]But seriously, emphasizing the difference between a large majority and a
tiny minority _is_ the acceptable use case for a pie chart, isn't it?

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TazeTSchnitzel
I suspect the flipped y axis was for sheer aesthetics - blood dripping down.

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nathancahill
I highly recommend reading "How to Lie with Statistics"[0]. Old but still very
relevant.

[0] [http://www.amazon.com/How-Lie-Statistics-Darrell-
Huff/dp/039...](http://www.amazon.com/How-Lie-Statistics-Darrell-
Huff/dp/0393310728)

~~~
sillysaurus3
I came here to say the same thing. Also
[http://www.statisticsdonewrong.com/](http://www.statisticsdonewrong.com/)

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andremendes
Great article, I've seen those techniques being used many times by brazilian
media. It's not easy to spot those lies at a glance but it's a must if you
don't want to get fooled by traditional media news.

~~~
vitorbaptistaa
(for Portuguese-speakers) I did a talk with the same title last year where I
showed a few more examples in [http://vitorbaptista.com/como-mentir-usando-
visualizacao-de-...](http://vitorbaptista.com/como-mentir-usando-visualizacao-
de-dados/#/)

These are only the slides, which lack lots of explanations, but might be
interesting to someone.

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jmharvey
The article doesn't even mention the most egregious offender on display in
their examples: the tilted/3-D pie chart. In the Romney/Palin/Huckabee
graphic, Palin's wedge has the smallest area, despite having the largest
number.

~~~
etler
That's a very good point, as it's commonly used but rarely pointed out. I feel
the examples in this article are very well known, but I never thought about
the impact of 3D charts. I suspect many people who use it do so without any
malicious intent, but just because they think it looks cool.

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MarcScott
This reminds me of an episode of The Saturday Night Armistice from way back in
1995

[https://www.youtube.com/watch?feature=player_detailpage&v=68...](https://www.youtube.com/watch?feature=player_detailpage&v=686tttWspnU#t=771)

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ASneakyFox
What about when people make charts where the x and y axises are unrelated or
stupid? If you plot oxygen consumption and death you'd find that almost all
people who died last year consumed oxygen.

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dsugarman
a logarithmic or exponential scale could be effective in lying as well

