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st: RE: running sum with two conditions - spells and time

From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   st: RE: running sum with two conditions - spells and time
Date   Thu, 31 Jan 2008 21:19:09 -0000

Successful uses of -tsspell- should be matched by donations to the
Hogwarts Rebuilding Fund. 

You now have a structure given first by panel identifier -dispno2- and
second by spell identifier -_spell-. 

Within that cumulative sums are defined by 

. bysort dispno2 _spell (date) : gen sum_stale = sum(stale) 

And the sum of the last five dates is then 

. by dispno2 _spell : gen prev5 = sum_stale - sum_stale[_n - 60] 

The last device I learned from Michael Blasnik. 

[email protected] 

Benjamin Appel

I have a unbalanced panel data set with monthly observations. The panel
id is: dispno2 and the time id is: date (formatted %tm). The variable of
interest is called: stale. It is a dummy variable (0/1) that measures
stalemates in negotiations. I would like to generate a running sum, but
with two conditions. First, the sum restarts after stale is 0 and the
sum only counts consecutive stalemates in the past 60 months. 

More clearly, I would like to generate a variable that counts the
consecutive number of stalemates (stale=1) in the past five years.

Similar questions have been discussed at length on the Statalist, but I
haven't been able to figure it out. Based on the thread at
( I was
able to use the user written tool tsspell to solve the problem of
restarting after every zero (or missing value based on the thread), but
I can't quite figure out how to create a five year running sum within
each spell. My completely copied code is below. Any help would be
greatly appreciated. Thank you very much!

tsset dispno2 date
tsspell, cond(!missing(stale))


gen stalecon=.
bysort dispno2 (date): replace stalecon=cond(missing(stale[_n-1]),
stale, stale+stalecon[_n-1])

*replaced stale=0 with missing to follow code on Statalist

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