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Re: st: Start/End dates to ongoing count indicators
From
Jeremy Wells <[email protected]>
To
[email protected]
Subject
Re: st: Start/End dates to ongoing count indicators
Date
Tue, 23 Apr 2013 12:40:35 -0500
I think that got it, but I needed to use -collapse- instead because I also had
some interval-level variables that needed to be summed.
Thanks!
Jeremy Wells
Ph.D. Student
LSU Dept. of Poli. Sci.
324 Stubbs Hall
Baton Rouge, LA 70803
I assume numeric variables with formats showing Stata weekly dates.
First you need an observation identifier
gen long obsid = _n
and then a duration count
gen duration = EndDt - StDt + 1
and then you want one observation per week
expand duration
Tidy up the dates
bysort obsid : gen Week = StDt[1] + _n - 1
Then
contract Week Class
and finally it's a -reshape-.
Nick
[email protected]
On 23 April 2013 17:04, Jeremy Wells <
[email protected]
> wrote:
> I have a dataset where observations are unique projects. Each project
> has a start week and end week variable, as well as a classification variable,
> so the data structure looks like this:
>
> StDt EndDt Class
> 2002wk1 2002 wk3 1
> 2002wk4 2002wk6 1
> 2002wk1 2002wk5 2
> 2002wk4 2002wk5 2
>
> What I would like to have is time series data with each observation a week
> and variables for each class with a count of the number of ongoing projects
> in each class in each week, so the data would look like this:
>
> Week Class1 Class2
> 2002 wk1 1 1
> 2002wk2 1 1
> 2002wk3 1 1
> 2002wk4 1 2
> 2002wk5 1 2
> 2002wk6 1 0
>
> The first though is -tab class, gen(class)-, but that will give me a 1 for the
> start week only, but I want the count to continue to the end week.
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