Does gen,sum() and egen,total() work differently when combined with bysort?

[Titir Bhattacharya]

Hi,

Please consider the following data:

* Example generated by -dataex-. For more info, type help dataex
clear
input float(distid hospid number)
1 1 10
1 2 10
1 3 10
2 2 12
2 1 12
2 3 12
3 2 13
3 3 13
3 1 13
end

I used sum() and total() combined with bysort but got different results. Do sum() and total() work differently when combined with bysort?

sort distid hospid

.
. by distid: gen sum=sum( number )

.
. by distid: egen total=total( number )

and it produced the following:

* Example generated by -dataex-. For more info, type help dataex
clear
input float(distid hospid number sum total)
1 1 10 10 30
1 2 10 20 30
1 3 10 30 30
2 1 12 12 36
2 2 12 24 36
2 3 12 36 36
3 1 13 13 39
3 2 13 26 39
3 3 13 39 39
end

[Carlo Lazzaro]

Titir:
-sum()- produces the running sum of the values observed for each -id-;
-total- from -egen- gives back a constant=to the sum of the values observed for each -id-.

[Titir Bhattacharya]

Titir:
-sum()- produces the running sum of the values observed for each -id-;
-total- from -egen- gives back a constant=to the sum of the values observed for each -id-.

Thanks Carlo!
I was really confused by this. Much appreciated

[Nick Cox]

help sum()

explains. Tip: firing up help with a function name and parentheses () takes you straight to specific help.