-viewsource _growtotal.ado- shows that treating missings as 0 is exactly
what -egen, rowtotal()- does. 
Nick 
[email protected] 
David Bell
You have surmised that -egen newvar = rowtotal(var1 var2)- treats  
missing values as zero.  I do not believe this is strictly correct.   
The command just sums the values that it has (thus not using a  
variable in a sum is the same as treating it as zero).  This is why I  
always use -rowmean- instead of -rowtotal-.  Thus when there is a  
missing value, you get the mean of the remaining values (they are not  
treated as zeros).
On May 15, 2008, at 12:31 AM, Yamamoto, Satomi wrote:
> I think  egen newvar = rowtotal(var1 var2) is equivalent to  
> replacing missing values with 0(zero).
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