Expanding panel data

[Dario Maimone Ansaldo Patti]

Dear All,

I have a strongly balanced panel dataset. An example is below:

* Example generated by -dataex-. For more info, type help dataex
clear
input float id int year str9 iso3 str35 country str9 hdicode str3 region int ccode
1 1990 "AFG" "Afghanistan" "Low"  "SA"  700
1 1991 "AFG" "Afghanistan" "Low"  "SA"  700
1 1992 "AFG" "Afghanistan" "Low"  "SA"  700
1 1993 "AFG" "Afghanistan" "Low"  "SA"  700
1 1994 "AFG" "Afghanistan" "Low"  "SA"  700
1 1995 "AFG" "Afghanistan" "Low"  "SA"  700
1 1996 "AFG" "Afghanistan" "Low"  "SA"  700
1 1997 "AFG" "Afghanistan" "Low"  "SA"  700
1 1998 "AFG" "Afghanistan" "Low"  "SA"  700
1 1999 "AFG" "Afghanistan" "Low"  "SA"  700
1 2000 "AFG" "Afghanistan" "Low"  "SA"  700
1 2001 "AFG" "Afghanistan" "Low"  "SA"  700
1 2002 "AFG" "Afghanistan" "Low"  "SA"  700
1 2003 "AFG" "Afghanistan" "Low"  "SA"  700
1 2004 "AFG" "Afghanistan" "Low"  "SA"  700
1 2005 "AFG" "Afghanistan" "Low"  "SA"  700
1 2006 "AFG" "Afghanistan" "Low"  "SA"  700
1 2007 "AFG" "Afghanistan" "Low"  "SA"  700
1 2008 "AFG" "Afghanistan" "Low"  "SA"  700
1 2009 "AFG" "Afghanistan" "Low"  "SA"  700
1 2010 "AFG" "Afghanistan" "Low"  "SA"  700
1 2011 "AFG" "Afghanistan" "Low"  "SA"  700
1 2012 "AFG" "Afghanistan" "Low"  "SA"  700
1 2013 "AFG" "Afghanistan" "Low"  "SA"  700
1 2014 "AFG" "Afghanistan" "Low"  "SA"  700
1 2015 "AFG" "Afghanistan" "Low"  "SA"  700
1 2016 "AFG" "Afghanistan" "Low"  "SA"  700
1 2017 "AFG" "Afghanistan" "Low"  "SA"  700
1 2018 "AFG" "Afghanistan" "Low"  "SA"  700
1 2019 "AFG" "Afghanistan" "Low"  "SA"  700
1 2020 "AFG" "Afghanistan" "Low"  "SA"  700
1 2021 "AFG" "Afghanistan" "Low"  "SA"  700
1 2022 "AFG" "Afghanistan" "Low"  "SA"  700
2 1990 "ALB" "Albania"     "High" "ECA" 339
2 1991 "ALB" "Albania"     "High" "ECA" 339
2 1992 "ALB" "Albania"     "High" "ECA" 339
2 1993 "ALB" "Albania"     "High" "ECA" 339
2 1994 "ALB" "Albania"     "High" "ECA" 339
2 1995 "ALB" "Albania"     "High" "ECA" 339
2 1996 "ALB" "Albania"     "High" "ECA" 339
2 1997 "ALB" "Albania"     "High" "ECA" 339
2 1998 "ALB" "Albania"     "High" "ECA" 339
2 1999 "ALB" "Albania"     "High" "ECA" 339
2 2000 "ALB" "Albania"     "High" "ECA" 339
2 2001 "ALB" "Albania"     "High" "ECA" 339
2 2002 "ALB" "Albania"     "High" "ECA" 339
2 2003 "ALB" "Albania"     "High" "ECA" 339
2 2004 "ALB" "Albania"     "High" "ECA" 339
2 2005 "ALB" "Albania"     "High" "ECA" 339
2 2006 "ALB" "Albania"     "High" "ECA" 339
2 2007 "ALB" "Albania"     "High" "ECA" 339
2 2008 "ALB" "Albania"     "High" "ECA" 339
2 2009 "ALB" "Albania"     "High" "ECA" 339
2 2010 "ALB" "Albania"     "High" "ECA" 339
2 2011 "ALB" "Albania"     "High" "ECA" 339
2 2012 "ALB" "Albania"     "High" "ECA" 339
2 2013 "ALB" "Albania"     "High" "ECA" 339
2 2014 "ALB" "Albania"     "High" "ECA" 339
2 2015 "ALB" "Albania"     "High" "ECA" 339
2 2016 "ALB" "Albania"     "High" "ECA" 339
2 2017 "ALB" "Albania"     "High" "ECA" 339
2 2018 "ALB" "Albania"     "High" "ECA" 339
2 2019 "ALB" "Albania"     "High" "ECA" 339
2 2020 "ALB" "Albania"     "High" "ECA" 339
2 2021 "ALB" "Albania"     "High" "ECA" 339
2 2022 "ALB" "Albania"     "High" "ECA" 339
3 1990 "DZA" "Algeria"     "High" "AS"  615
3 1991 "DZA" "Algeria"     "High" "AS"  615
3 1992 "DZA" "Algeria"     "High" "AS"  615
3 1993 "DZA" "Algeria"     "High" "AS"  615
3 1994 "DZA" "Algeria"     "High" "AS"  615
3 1995 "DZA" "Algeria"     "High" "AS"  615
3 1996 "DZA" "Algeria"     "High" "AS"  615
3 1997 "DZA" "Algeria"     "High" "AS"  615
3 1998 "DZA" "Algeria"     "High" "AS"  615
3 1999 "DZA" "Algeria"     "High" "AS"  615
3 2000 "DZA" "Algeria"     "High" "AS"  615
3 2001 "DZA" "Algeria"     "High" "AS"  615
3 2002 "DZA" "Algeria"     "High" "AS"  615
3 2003 "DZA" "Algeria"     "High" "AS"  615
3 2004 "DZA" "Algeria"     "High" "AS"  615
3 2005 "DZA" "Algeria"     "High" "AS"  615
3 2006 "DZA" "Algeria"     "High" "AS"  615
3 2007 "DZA" "Algeria"     "High" "AS"  615
3 2008 "DZA" "Algeria"     "High" "AS"  615
3 2009 "DZA" "Algeria"     "High" "AS"  615
3 2010 "DZA" "Algeria"     "High" "AS"  615
3 2011 "DZA" "Algeria"     "High" "AS"  615
3 2012 "DZA" "Algeria"     "High" "AS"  615
3 2013 "DZA" "Algeria"     "High" "AS"  615
3 2014 "DZA" "Algeria"     "High" "AS"  615
3 2015 "DZA" "Algeria"     "High" "AS"  615
3 2016 "DZA" "Algeria"     "High" "AS"  615
3 2017 "DZA" "Algeria"     "High" "AS"  615
3 2018 "DZA" "Algeria"     "High" "AS"  615
3 2019 "DZA" "Algeria"     "High" "AS"  615
3 2020 "DZA" "Algeria"     "High" "AS"  615
3 2021 "DZA" "Algeria"     "High" "AS"  615
3 2022 "DZA" "Algeria"     "High" "AS"  615
end

I would like to expand the time coverage for each panel, adding observations from 1970 to 1989. While I find easy to balance the panel if unbalanced, I am not sure about how to proceed in this case. Do you have any suggestion to share?

Thaks in advance for any help you may provide.

Dario

[Clyde Schechter]

insobs 1, before(1)
replace id = 1 in 1
replace year = 1970 in 1
xtset id year
tsfill, full

foreach v of varlist iso3-region {
    by id (`v'), sort: replace `v' = `v'[_N]
}
by id (ccode), sort: replace ccode = ccode[1]

isid id year, sort

[Dario Maimone Ansaldo Patti]

Clyde Schechter Thanks a lot. Helpful as usual!!