# Re: st: Drawing confidence limit lines

 From "roland andersson" <[email protected]> To [email protected] Subject Re: st: Drawing confidence limit lines Date Sat, 13 Jan 2007 10:05:59 +0100

```I want to make a graph similar to the one's you can find in this reference

Tekkis, P. P et al. Mortality control charts for comparing
performance of surgical units: validation study using hospital
mortality data. BMJ 2003;326:786 ( 12 April )

Greetings

```
```Read carefully.
I understand Svend's reference as drawing confidence intervals around
each observed value. I do not want that. I gives a graph that is
difficult to read as many hospitals I want observed value as plots
against a background with confidence limits around the reference value
at increasing numbers on the x-axis.

I will rephrase my question:

How can I draw confidence limits for a reference proportion
(proportion of deaths) at increasing number of operations, from 30 to
400?  How can I combine such a graph with plots of observed mortality?

Greetings

2007/1/12, Svend Juul <[email protected]>:
>
> I want to draw lines along the x-axis that show the limit
> of the 90 and 95% confidence interval for a mortality of 0.15%
> at increasing number of operations. I than will plot the
> results of each hospital. This will show the widening CI for
> the smaller hospitals and the distance from this CI line of each
> hospital in relation to the number of operations performed, I have
> used "by hospital: ci mortality, poisson" to calculate the CI for
> each hospital. I could plot these CI for each hospital to show the
> hospitals which has a lower CI above the mean, but I want rather the
> CI lines for the mean mortality and plot the hospitals as points.
> ---------------------------------------------------
>
> I am not sure about the soundness of putting confidence intervals
> around both the reference value (0.15%) and the observed values.
>
> Apart from that: I think you might benefit from -statsby-; see
> [D] statsby.
>
> Hope this helps
> Svend
>
> ________________________________________________________
>
> Svend Juul
> Institut for Folkesundhed, Afdeling for Epidemiologi
> (Institute of Public Health, Department of Epidemiology)
> Vennelyst Boulevard 6
> DK-8000 Aarhus C,  Denmark
> Phone, work:  +45 8942 6090
> Phone, home:  +45 8693 7796
> Fax:          +45 8613 1580
> E-mail:       [email protected]
> _________________________________________________________
>
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

```
```*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```