Creating 'active' variable for panel data

[Sukhun Kang]

Hi all, I have a question related to constructing a variable in panel.

I want to create a variable that captures the activeness of the organization.

I have a panel organization-year data where I have a variable that captures the # of events per year. Essentially my data looks like the following.

organization year #_events
1 1990 0
1 1991 0
1 1992 1
1 1993 2
1 1994 0
1 1995 0
1 1996 1

I want to construct a variable that captures the activeness of the organization. I want it to be coded as 1 if the org had at least one event in past n years including the current year. For example, if it is 3, the 'active' will equal to 1 starting from 1992 to 1996. However, if n=2, the active will equal to 1 from 1992 to 1994, and 0 for 1995, and then 1 for 1996 again.

I would think that I can use combination of by and sort but I have no clue how to do them. Please advice!

Many thanks in advance.

-S

[Nick Cox]

You can use rangestat (SSC) for this purpose. You look for the maximum in a moving window and then reduce it to a (0, 1) indicator. Here is an example.

clear 
input organization year n_events
1 1990 0
1 1991 0
1 1992 1
1 1993 2
1 1994 0
1 1995 0
1 1996 1
end 

rangestat (max) n2=n_events, int(year -1 0) by(org) 
rangestat (max) n3=n_events, int(year -2 0) by(org) 

replace n2 = n2 > 0 
replace n3 = n3 > 0 

list, sep(0) 


     +--------------------------------------+
     | organi~n   year   n_events   n2   n3 |
     |--------------------------------------|
  1. |        1   1990          0    0    0 |
  2. |        1   1991          0    0    0 |
  3. |        1   1992          1    1    1 |
  4. |        1   1993          2    1    1 |
  5. |        1   1994          0    1    1 |
  6. |        1   1995          0    0    1 |
  7. |        1   1996          1    1    1 |
     +--------------------------------------+

For the announcement of rangestat, see https://www.statalist.org/forums/for...s-within-range

For other examples, search this forum with rangestat as key word.

[Sukhun Kang]

Amazing. Thanks for your help!