Adding events per country and year

[Alberto Ramon]

Hi Statalisers,

I have been a frequent user but this is my first time posting. I'm using Stata 14.2 and I have a dataset of conflict events that contains 14,000 observations with seven variables. I want to create one variable that counts the total events by year for each country. As you see there is already a variable that does this (tot_yr_inc). However, some are multi-year events so I want to count those events as part of the total events for that continuing year (this is what the variable is for new_tot) . For example, in the eight observation the start year (styr) is 2002 but the end year (eyr) is 2004 so the total for 2003 should be 5 (not 4) and the total for 2004 should be 4 (not 3).

The variables are defined as:
country - the country the event occurred
styr - The year the event started
eyr - The year the event ended
yr_id - An identifier for the year-country pair
yr_inc_num - The incident number for that year (Used as a count for the events of the year)
tot_yr_inc - Total events for that year-country pair
new_tot - New variable created to account for the continuous events

The snippet of my data is as follows:

* Example generated by -dataex-. To install: ssc install dataex
clear
input long country int(styr eyr) float(yr_id yr_inc_num tot_yr_inc new_tot)
10 2000 2000 1 1 3 3
10 2000 2000 1 2 3 3
10 2000 2000 1 3 3 3
10 2001 2001 2 1 2 2
10 2001 2001 2 2 2 2
10 2002 2002 3 1 4 4
10 2002 2002 3 2 4 4
10 2002 2004 3 3 4 4
10 2002 2002 3 4 4 4
10 2003 2003 4 1 4 4
10 2003 2003 4 2 4 4
10 2003 2003 4 3 4 4
10 2003 2003 4 4 4 4
10 2004 2004 5 1 3 3
10 2004 2004 5 2 3 3
10 2004 2004 5 3 3 3
12 1990 1990 6 1 3 3
12 1990 1990 6 2 3 3
12 1990 1990 6 3 3 3
12 1991 1991 7 1 3 3
12 1991 1992 7 2 3 3
12 1991 1991 7 3 3 3
12 1992 1992 8 1 2 2
12 1992 1992 8 2 2 2
12 1993 1993 9 1 2 2
12 1993 1993 9 2 2 2
end
label values country country
label def country 10 "Cote d'Ivoire", modify
label def country 12 "Democratic Republic of the Congo", modify

I have been trying to do this using a loop and the code runs without any errors but nothing changes. I have messed with it and understand why it doesn't work but at this point I am stuck. I am not sure what else to do. I would greatly appreciate your help.

forval c=1/9 {
                if styr<eyr & yr_id==`c'{
                local pair=eyr if yr_id==`c'
                local group=yr_id if `pair'==`pair' 
                replace new_tot=new_tot + 1 if yr_id>`c' & yr_id<`group'
                }
                else {
                }
    }