generate new variable using egen with sum/count

[Yusuf Martak]

Hello everyone, hope you all have a good day ahead.

So i want to ask 1 question.. i have a data set which consist of ID, Year, Dummy_rich.

Year ID rich
2005 1101 0
2006 1101 0
2007 1101 1
2008 1101 0
2009 1101 0
2010 1101 1
2011 1101 1
2012 1101 0
2013 1101 1
2005 1102 0
2006 1102 0
2007 1102 0
2008 1102 0
2009 1102 1
2010 1102 1
2011 1102 0
2012 1102 1
2013 1102 2
2005 1103 1
2006 1103 0
2007 1103 1
2008 1103 1
2009 1103 0
2010 1103 3
2011 1103 1

Then i want to create one other variable which formed by the calculation of sum dummy_rich, but in different way. i don't know what is the name of this form. here it is

Year ID rich sum_rich
2005 1101 0 0
2006 1101 0 0
2007 1101 1 1
2008 1101 0 1
2009 1101 0 1
2010 1101 1 2
2011 1101 1 3
2012 1101 0 3
2013 1101 1 4
2005 1102 0 0
2006 1102 0 0
2007 1102 0 0
2008 1102 0 0
2009 1102 1 1
2010 1102 1 2
2011 1102 0 2
2012 1102 1 3
2013 1102 2 5
2005 1103 1 1
2006 1103 0 1
2007 1103 1 2
2008 1103 1 3
2009 1103 0 3
2010 1103 3 6
2011 1103 1 7

Do you guys could help me to find out what is the name of this form and the syntax which i could use in stata? Thank you so much.

ohya Fyi, i already tried several syntax such as egen count, egen sum, egen total, gen _n and so on..

[Nick Cox]

I would call that a cumulative or running sum, and it is what the function sum() provides.

help sum()

clear 
input Year ID rich 
2005 1101 0
2006 1101 0
2007 1101 1
2008 1101 0
2009 1101 0
2010 1101 1
2011 1101 1
2012 1101 0
2013 1101 1
2005 1102 0
2006 1102 0
2007 1102 0
2008 1102 0
2009 1102 1
2010 1102 1
2011 1102 0
2012 1102 1
2013 1102 2
2005 1103 1
2006 1103 0
2007 1103 1
2008 1103 1
2009 1103 0
2010 1103 3
2011 1103 1
end 

bysort ID (Year) : gen wanted = sum(rich) 

list, sepby(ID) 

     +-----------------------------+
     | Year     ID   rich   wanted |
     |-----------------------------|
  1. | 2005   1101      0        0 |
  2. | 2006   1101      0        0 |
  3. | 2007   1101      1        1 |
  4. | 2008   1101      0        1 |
  5. | 2009   1101      0        1 |
  6. | 2010   1101      1        2 |
  7. | 2011   1101      1        3 |
  8. | 2012   1101      0        3 |
  9. | 2013   1101      1        4 |
     |-----------------------------|
 10. | 2005   1102      0        0 |
 11. | 2006   1102      0        0 |
 12. | 2007   1102      0        0 |
 13. | 2008   1102      0        0 |
 14. | 2009   1102      1        1 |
 15. | 2010   1102      1        2 |
 16. | 2011   1102      0        2 |
 17. | 2012   1102      1        3 |
 18. | 2013   1102      2        5 |
     |-----------------------------|
 19. | 2005   1103      1        1 |
 20. | 2006   1103      0        1 |
 21. | 2007   1103      1        2 |
 22. | 2008   1103      1        3 |
 23. | 2009   1103      0        3 |
 24. | 2010   1103      3        6 |
 25. | 2011   1103      1        7 |
     +-----------------------------+