[R] Can we get rid of bar charts with error bars?

[Greg Snow]

This reminds me of a quote I saw once (I think it may have been in one of those Murphy's Laws calendars), my parahpase:

If you make someone think that they are thinking,
	They will love you for it.
If you make them actually think,
	They will hate you for it.

This explains why people love pie charts and hate more effective graphs.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Jim Lemon
> Sent: Thursday, December 03, 2009 7:58 PM
> To: Frank E Harrell Jr
> Cc: r-help at r-project.org
> Subject: Re: [R] Can we get rid of bar charts with error bars?
> 
> On 12/04/2009 12:56 AM, Frank E Harrell Jr wrote:
> > Bar charts with error bars are far inferior to dot charts and other
> > types of displays.  One of many problems is demonstrated if you draw
> a
> > bar chart displaying temperature in F then re-draw it on the degrees
> C
> > scale.  See http://biostat.mc.vanderbilt.edu/DynamitePlots for much
> > more information.  The error bars lull us into an assumption that
> > symmetric confidence intervals are OK, among other things.
> >
> > Frank
> >
> I could promote the "dispersion" function as capable of displaying
> asymmetric confidence intervals on whatever location indicators you
> prefer (have a look at the second example for "hierobarp" for example),
> but the problem is deeper than that. The point of graphic displays is
> to
> convey information to someone else, not to tell ourselves what we
> already know. Do people cheat with pie charts, bar charts, etc? Sure,
> and we could cheat with dot charts, too. Graphic displays are typically
> shown to an audience that knows less about the topic than the presenter
> in the hope that an obscure relationship will be clarified. If I am
> presenting to colleagues in my field, I will use much more informative
> and difficult to understand graphics than if I am summarizing the same
> results to the general public. If both groups leave the respective
> presentations enlightened, I have done well.
> 
> Jim
> 
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