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| From | Steven Samuels <sjsamuels@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: RE: dates |
| Date | Thu, 6 Oct 2011 18:50:29 -0400 |
With enough missing dates it might be better to randomly assign a day of the month, or you risk distorting the distribution of inter-visit intervals.
Steve
*********************************
clear
input str10 date
200801
20080113
end
set seed 21932
gen visdate = date(date, "YMD")
tempvar day
gen str2 `day' = string(ceil(15*runiform())) if length(date)==6
replace `day' = "0"+`day' if real(`day')<10
gen fakeday = (length(date)==6)
replace visdate = date(date + `day', "YMD") if length(date)==6
format visdate %td
list date visdate fakeday
*****************************
On Oct 6, 2011, at 5:46 PM, Michael Eisenberg wrote:
Thanks so much.
On Thu, Oct 6, 2011 at 8:23 AM, Nick Cox <n.j.cox@durham.ac.uk> wrote:
> You don't say what "without success" means precisely.
>
> "200801" does not match either date pattern. If there is no information on day of month, Stata can only return missing for a daily date.
>
> -date("200801" + "15", "YMD")- seems to be the most common fudge. I would always tag such guessed dates with an indicator variable.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Michael Eisenberg
>
> I have a list of visit dates for patients. Unfortunately, the format
> is not constant.
>
> Most are listed with the year, month, day such as 20080105 for Jan 5,
> 2008 but some are listed only with the year and month 200801 for Jan
> 2008.
>
> I attempted to convert them into stata dates with the commands below
> without success.
>
> gen ndate = date(dx_date, "YMD")
> or
> gen ndate = date(dx_date, "CCYYNNDD")
>
> Can stata handle such inconsistent data?
>
>
> *
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>
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