The whole area is discussed in excruciating detail
in
Graphing agreement and disagreement.
Stata Journal 4(3): 329--349 (2004)
This reveals some different approaches
to the problem, based on -pairplot- and -linkplot-
from SSC. Among several other details, -pairplot-
points to a useful reference
McNeil, D.R. 1992. On graphing paired data.
American Statistician 46, 307-11.
which contains a critique of the kind of graph
you have in mind (although -linkplot- will
do most or perhaps even all of what you want).
Nick
[email protected]
David Fisher
> I am working on a study where a group of women were measured
> before and
> after a month during which they were given a nutritional supplement
> intervention. I would like to create a graph with a line for
> each subject
> (overlaid on the same plot), joining their "before" and
> "after" measurements
> for a particular variable (blood vitamin B12, say). I can do
> this, roughly,
> by using the "tsset" and "xtline, overlay" commands.
> What I am having trouble with, however, is controlling the
> look of these
> lines. The nature of the "xtline, overlay" command seems to
> be that you
> have to alter each line individually using the "plopts#"
> option. Using a
> local macro to create a huge line of text to alter each line
> one after the
> other doesn't work because would be "too many options". Is
> there a way to
> change all the lines at once (specifically, I would like them
> to be all the
> same colour, or ideally one of 3 colours depending on their
> supplement
> category)? E.g. can I say something like "plopts1/77()"
> (this doesn't work,
> by the way!) Or, failing that, is there a completely
> different approach to the problem?
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