On Fri, Mar 13, 2009 at 6:10 PM, Maarten buis <[email protected]> wrote:
>
> --- On Fri, 13/3/09, Tiago V. Pereira wrote:
>> That estimate of 4.5 is actually the risk ratio, isn´t it?
>> Or am I doing a big confusion?
>
>
> I assume you refer to this -koopmani-:
> STB-58 sg154 . Conf. int. for ratio of two binomial prop. by Koopman's method (help koopman if installed) .. . . . . . . . . . . . . . D. Wang
> 11/00 pp.16--19; STB Reprints Vol 10, pp.244--247
>
> From the helpfile of -koopmani-: "koopman computes the confidence
> intervals for the ratio of two binomial proportions", so it is a risk
> ratio not an odds ratio.
>
> -- Maarten
-koopmani- seems to have a programming issue as well as that labelling issue:
. sysuse auto, clear
(1978 Automobile Data)
. koopmani 36 40 16 80
m ambiguous abbreviation
r(111);
. drop make
. koopmani 36 40 16 80
| Event | Proportion
| Yes No | Total Yes
-----------------+------------------------+----------------------
Group1 | 36 -14 | 22 1.6364
Group2 | 16 64 | 80 0.2000
-----------------+------------------------+----------------------
Total | 52 50 | 102 0.5098
| |
| Point estimate | [95% Conf. Interval]
-----------------|------------------------+----------------------
Odds Ratio | 8.181818 | 7.313014 12.16772
-----------------------------------------------------------------
. drop _all
. koopmani 36 40 16 80
| Event | Proportion
| Yes No | Total Yes
-----------------+------------------------+----------------------
Group1 | 36 4 | 40 0.9000
Group2 | 16 64 | 80 0.2000
-----------------+------------------------+----------------------
Total | 52 68 | 120 0.4333
| |
| Point estimate | [95% Conf. Interval]
-----------------|------------------------+----------------------
Odds Ratio | 4.5 | 2.939633 7.152252
-----------------------------------------------------------------
I suspect koopmani.ado would benefit from some -tempvar- or tempname-
statements.
Roger.
--
Roger Harbord
http://www.epi.bris.ac.uk/staff/rharbord.htm
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