Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down on April 23, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Generating new variables with values of difference in 2 variables


From   Hitesh Chandwani <hchandwani.stata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Generating new variables with values of difference in 2 variables
Date   Wed, 18 Apr 2012 21:12:13 -0500

This works great! Thanks Nick.
This is not panel data; I'm using claims data to calculate compliance
with medications for which I need each patient to have a single row of
data (I converted the original long form to wide form data).

I have another question though:

I am interested in the first day that there was a break in medication
possession. From the date variables (disp_date1-disp_date14 OR
disp_date`k'), I need to pick out the first date of the break. In
other words, I need to pick out the first date for each patient where
variable A`k' > variable B`k'.

I've been trying for hours but I can't get Stata to do exactly what I
want. I tried -egen-, and some loops but to no avail.

Does someone have any inputs?

Hitesh


On Wed, Apr 18, 2012 at 11:06 AM, Nick Cox <njcoxstata@gmail.com> wrote:
> forval j = 1/7 {
>     local J = `j' + 1
>     gen var`j' = day`J' - day`j'
> }
>
> or
>
> forval j = 1/7 {
>    gen var`j' = day`=`j' + 1' - day`j'
> }
>
> All that said, this sounds a very bad idea strategically. Presumably
> -day1- is what happens on day 1, and so forth, so this is time series
> or panel data. You start out with 8 day variables, then add 7
> difference variables. When this is going to stop as you add further
> analyses?
>
> Better to -reshape long-. Then you can work with one response
> variable, one set of differences, etc.
>
> Nick
>
> On Wed, Apr 18, 2012 at 4:59 PM, Hitesh Chandwani
> <hchandwani.stata@gmail.com> wrote:
>
>> This is another query about loops. I have 8 variables day1-day8. I am
>> trying to run a loop that does:
>>
>> gen var1=day2-day1
>> gen var2=day3-day2
>> gen var3=day4-day3...and so on.
>>
>> From previous statlist emails, I found how to run loops subtracting
>> one series of variables from another
>> (http://www.stata.com/statalist/archive/2012-01/msg00303.html), but
>> I'm having a hard time trying to generate a loop where variables
>> within the same series are subtracted from each other.
> *
> *   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/



-- 
Hitesh S. Chandwani
University of Texas at Austin

*
*   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/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index