st: counting number of children in a household

[Scott Cunningham <scunning@gmail.com>]

Thanks to those who answered my last question.  I have one more now.   
I need to count how many children are in a given household and assign  
this number to each individual in the same household.

I do not have a specific household id, but rather, I can distinguish  
households by first, the state id (ent), then the municipality id  
(mun), then the community id (numviv), and then household number  
(numhog).

I tried to count as follows:

*Number of Children in the house
*Assume a child in Mexico is less than or equal to 18 years of age
by ent mun numviv numhog: count if age<=18
by ent mun numviv numhog: gen num_child_h=r(N)

My data looks like this:

State     Municipality     Community       Household            
Person      Age
GA              5                      4                      
1                    Dave         50
GA              5                      4                   &! ! nbsp;  
1                    Diane        10
GA              5                      3                      
1                    Linda          5
GA              5                      3                      
1                    Stef           45
GA              5                      3                      
2                    David         50
GA              5                      3                      
2                    Jane          30
GA              5                      2                      
1                    Smith        62
GA              5                      2                      
1                    Nancy        12

Also, can I some how, assign a specific household id number such that  
I do not have to look at the state, the municipality, the community  
and then the household.
 
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