Re: st: simulating data for logistic regression: translating R toStata

[Michael McCulloch <mm@pinest.org>]

Thank you Maarten. This worked very well. The complete code for my 
simulation of data for logistic regression is as follows. From your 
article, I learned how to write the code for generating  disease 
variable -y-.

clear
set mem 1g
set obs 100000				//create 1000 observations
gen id=_n				//Create ID numbers
set seed 12358				//set random number seed for 
reproducibility
gen treat= 1 + int(2*uniform())	//treatment: discrete uniform random 
variables, 1 or 2
gen comorb= 1 + int(4*uniform())	//# of comorbid conditions: 1,2,3, or 4
gen age=50+10 * invnorm(uniform()) //  create age, with mean 50 and sd==10
gen chol = 200+25 * invnorm(uniform())	// create cholesterol, with 
mean 200 and sd==25
gen wt = 150+20 * invnorm(uniform())	// create cholesterol, with 
mean 200 and sd==25
gen sex= 1 + int(2*uniform())	// create sex: discrete uniform 
random variables, 1 or 2
replace sex=0 if sex==2
* Specify population model for log odds that Y=1
gen y = uniform() < invlogit(-3 + .1*(comorb-2) + .045*(age-50) + (-2*(treat)))
logit y treat comorb age // note that regression coefficients 
approximate those specified




> --- Michael McCulloch <mm@pinest.org> wrote:
> >  I'm simulating data for logistic regression (code for variable
> >  generation is below) , and am missing the last step, linking
> >  exposureto disease. Disease will be a y/n variable.
> This was discussed in M.L. Buis (2007) "Stata tip 48: Discrete uses for
> uniform()" The Stata Journal, Vol. 7 No. 3, pp. 434-435.
> http://home.fsw.vu.nl/m.buis/wp/discrete.html
>
> Hope this helps,
> Maarten
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting address:
> Buitenveldertselaan 3 (Metropolitan), room Z434
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
>       __________________________________________________________
> Sent from Yahoo! Mail.
> A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html
> *
> *   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/