Ernest Berkhout
> so far I was not able to detect an option in Stata 8 graphs
> to display an
> axis with the sort of layout that shows that is does not
> start 'naturally'
> at the zero-point. Visually, I mean something like this:
>
> |
> 6
> |
> 5
> |
> >
> <
> |
> +-----
>
> Is it possible but did I overlook that? Or is it not an
> option yet? In the
> second case, are the Stata people willing to introduce
> something like that
> in the future? From the 'How to lie with statistics'-line
> of thought my
> opinion is that this would make a lot of sense for people
> when submitting
> graphs to scientific papers.
Clearly you want this, and your main questions are
(1) can you do it in Stata 8? (I guess not)
(2) is it on Stata Corp to do list? (don't know)
Nevertheless I want to discuss the presumption here.
As I recall, Darrell Huff in his 1954 book implied that axes
which don't start at zero are deceitful. And I seem
to remember my high-school science teachers saying the
same thing in the 1960s and recommending a scale break.
But another point of view is this: if people can't be
bothered to look at the axes and read the labels,
then they won't understand the graph, and whose fault
is that?
William S. Cleveland in his book "The elements of
graphing data" (full reference in manuals) includes
the following advice:
Do not insist that zero always be included on a scale
showing magnitude. (p.92)
Following that, he clearly and firmly discusses
and dismisses the Huff dictum.
He also says
Use a scale break only when necessary.
If a break cannot be avoided, use a full scale break.
Do not connect numerical values on two sides of a
break. Taking logs can cure the need for a break. (p.104)
A full scale break is more than a squiggle on the axis.
It is a division into separate panels.
I don't think any time series graph for recent decades suffers
in the least from not having a scale break because it doesn't
go all the way back to a time origin, whether BC/AD
or the origin of the Earth or whatever.
My question, therefore:
are there literatures in which this is still standard?
Just curious.
P.S. There is a tip at
http://www.stata.com/support/faqs/graphics/scbreak.html
The following has been added, not by the author:
Note: This FAQ is relevant for users of releases prior to Stata 8
but the _idea_ about what to do is equally applicable
to Stata 8. All that has changed is the syntax to implement
it.
Nick
[email protected]
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