<>
What exactly is your problem with this output? -psmatch2- does not change
the marginal distribution of treated and untreated, and it is not supposed
to:
*************
webuse labor, clear
gen byte wc =we > 12
//see distribution
ta wc
//distribution reemerges after every command
psmatch2 wc wmed wfed, outcome(ww) neighbor(1) noreplace
psmatch2 wc wmed wfed, outcome(ww) kernel kerneltype(epan)
psmatch2 wc wmed wfed, outcome(ww) llr kerneltype(tricube)
*************
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von moleps islon
Gesendet: Donnerstag, 12. November 2009 17:29
An: [email protected]
Betreff: Re: st: RE: psmatch2 and stcox
Thx - for the first suggestion. However despite using the
noreplacement option I get the same output, ie not 1:1 matching :
xi:psmatch2 treatment `var',noreplacement neighbor(1) common out(dead)
| psmatch2:
psmatch2: | Common
Treatment | support
assignment | On suppor | Total
-----------+-----------+----------
Untreated | 628 | 628
Treated | 338 | 338
-----------+-----------+----------
Total | 966 | 966
Any clues?
Regards,
M
On Thu, Nov 12, 2009 at 3:23 PM, Villa Lora, Juan Miguel
<[email protected]> wrote:
> Hi!
> I've got suggestions:
> 1. Try to estimate the propensity score firstly (with a probit or logit)
and set the prediction in the option p(your_prediction). This saves you time
when running the command several times.
> 2. Specify the option "noreplacement" which yields a 1-1 matching as
wanted.
>
> JM.
>
> -----Original Message-----
> From: [email protected]
[mailto:[email protected]] On Behalf Of moleps islon
> Sent: Martes, 10 de Noviembre de 2009 03:28 p.m.
> To: [email protected]
> Subject: st: psmatch2 and stcox
>
> I´m trying to match 336 exposed patients from a cohort with a total of
> 966 patients using psmatch2:
>
> xi:psmatch2 E `var', outcome(out) neighbor(1) common
>
> I thought this would give me 1:1 matching, but I get 336 exposed and
> 662 control patients.
>
> Then doing
>
> ttest -different variables-, by(_t)
>
> doesnt really match very well despite reasonable overlapping propensity
distributions. Is this due to omitting the weighting option?
>
> I´d like to use these propensity matched data for a logrank test, but I´m
uncertain to the type of weight I should use. I assumed it should be
pweight, but I found another posting here where they said fweight leaving me
uncertain....
>
> Regards
>
> M
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
>
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
