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Re: st: multiple CI/mean plots in one graphic


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: multiple CI/mean plots in one graphic
Date   Thu, 28 Apr 2011 20:40:05 +0100

-civplot- is a user-written plot from SSC written in 1999 for Stata 6.
I am not surprised that it does not separate out different groups
given a command

. civplot variable1, by(time)

as the command does not even mention -group-. Also, as -njc_stuff-
(also SSC) documents, -civplot- is considered obsolete given -ciplot-
(also SSC).

But better than either is to do it yourself using the principles described in

Cox, N.J. 2010. Speaking Stata: The statsby strategy. Stata Journal
10, 143-151.
http://www.stata-journal.com/article.html?article=gr0045

The following problem has essentially similar structure to yours and
shows some technique

sysuse auto, clear
statsby mean=r(mean) ub=r(ub) lb=r(lb) , by(foreign rep78) : ci weight
separate mean, by(foreign) veryshortlabel
separate ub, by(foreign) veryshortlabel
separate lb, by(foreign) veryshortlabel
scatter mean0 mean1 rep78 || rcap ub0 lb0 rep78 || rcap ub1 lb1 rep78,
legend(order(1 2))

However, note that what you have done so far implies that separate
days are independent, which may not be quite right!

Nick

On Thu, Apr 28, 2011 at 6:33 PM, Pieter-Jan <duikerarts@home.nl> wrote:

> Recently we performed a randomized crossover study in which we monitored the
> lung function of a group of volunteers  during three days. Day 1 was used to
> determine baseline lung function whereas day 2 and 3 were used to monitor
> lung function after inhaling either placebo (air) or active gas (oxygen)
> under hyperbaric  condition. During each measurement day lung function was
> measured 6 times. All variables and observations were put in a dataset which
> initially had the following format:
>
> ID           Group                  Time                     Variable1 etc
> 1             0                      0                             6.19
> 2             0                      0                             5.97
> Etc
>
> ID exist of 13 persons
> Group: 0 (baseline), 1 (placebo), 2 (active)
> Time: 0, 2, 4, 8, 12, 22 hours after exposure
>
> To give the reader a good overview how f.e. variable 1 changes over time
> within the 3 groups I want to plot the CI and mean of each group on each
> time point in one graphic. I tried civplot
>
> Civplot variable1, by(time)
>
> But that gives me no separate plots of the three groups.
>
> I tried to change the dataset by deleting the group variable and changing
> the Variable1 etc as follows
>
> ID           Time      Variable1_baseline        Variable1_placebo
> Variable1_active etc
> 1             0             6.19                     6.01
> 6.11
> 2             0             5.97                     6.05
> 5.91
>
> Civplot variable1_baseline, by(time)
>
> This allows me only 1 civplot for each variable but just like the first
> attempt this gave me only 1 plot per graphic. I tried also twoway
>
> Twoway (scatter variable1_baseline time) (fpfit variable1_baseline time)
> (scatter variable1_placebo time) (fpfit variable1_placebo time) (scatter
> variable1_active time) (fpfit variable1_active time)
>
> And this gives the possibilities of putting multiple plots in one graphic
> but specially the scatter makes it cluttered. A simple CI/mean would
> counteract this.
>
> Is there a possibility in Stata of putting multiple CI/mean plots into one
> graphic? Maybe the answer speaks for itself but I am rather new into Stata
> that's why I asking this question.

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