Greatly appreciated - thank you Nick!
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Nick Cox
> Sent: Friday, February 21, 2003 1:57 PM
> To: [email protected]
> Subject: st: -catplot- available for download from SSC
>
>
> Thanks to Kit Baum, a new package -catplot-
> has been posted on SSC. This is for plots
> of categorical data in Stata 8, specifically
> for bar or dot charts of the same showing
> frequencies, or fractions, or percents.
>
> (For Stata 7 or earlier there are other
> user-written programs available in the same
> territory, such as -fbar-, -tabhbar-, -vbar-.)
>
> Those who have looked at Stata 8's new
> graphics may well ask: Surely all that is very
> well done in Stata 8, with -graph bar-, -graph
> hbar- and -graph dot- offering a great range of
> possibilities?
>
> The answer is "Yes indeed", and that is
> what I am building on, the aim being to add
> a convenience command in one particular
> area.
>
> I work a lot with students and others who want bar
> charts of categorical data, for example, of counts
> of categories from one-way, two-way or even three-way
> tables from questionnaires and other survey data.
> In addition, many of these users want to tell me
> for some reason that it's very easy in Excel, so
> I really want to be able to say to them that it's
> also very easy in Stata.
>
> How does Stata size up on this task?
>
> 1. -histogram- is optimised for histograms,
> naturally. It can be used for this purpose by
> invoking options like
>
> , discrete xla(, valuelabel ang(45)) gap(50)
>
> for a one-way table or
>
> , discrete xla(, valuelabel ang(45)) gap(50)
> by(myvar, rows(1))
>
> for a two-way table. Typing this -- or issuing
> the equivalent through a dialog -- is a
> little more complicated than some Stata beginners
> might expect for this task. In any case,
> some problems then frequently arise:
>
> a. it doesn't take much for value labels to become
> unreadable or to require what I call giraffe graphics,
> in which the graphic necessitates a great deal of neck
> movement. (That's why I have "ang(45)" in the examples
> above.)
>
> b. The number of cells you can show easily and effectively
> appears to be ~20, given that you will want value
> labels shown to indicate the categories. Any long
> value labels make this problem worse.
>
> c. Representing a 3-way table seems impossible, except by
> producing and then combining separate histograms.
>
> 2. -graph hbar- etc. is good _if_ the
> frequencies come predefined as a variable, because
> then you can just sum the frequencies. But
> if you want Stata to do the counting for you,
> this seems to require you to set up something
> to count. In particular,
>
> . graph hbar (count) rep78
>
> doesn't give you the frequencies of the
> categories of -rep78-. Roughly, we want -graph-
> here to -contract-, not -collapse-.
>
> The way to do it is to calculate something in
> advance, as in
>
> . gen freq = 1
> . graph hbar (count) freq, over(rep78)
>
> but arguably we shouldn't have to do that.
> And as for percents, catching missings,
> and working with -if- and -in-: it
> really needs a program.
>
> So that's the rationale for -catplot-. What it
> actually does can be seen by reading the help
>
> . ssc type catplot.hlp
>
> and then if interested you can install
>
> . ssc inst catplot
>
> Nick
> [email protected]
>
> P.S. choosing good names is not always
> easy. Perhaps this one is down partly
> to the fact that I like cats.
> *
> * For searches and help try:
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> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
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