st: new variables creation with unbalanced panel

[Laura <laura_sendrea@yahoo.com>]

Hi, I am very new at using STATA. Sorry for the previous post, in which the 
panel looked all wrong.
I am using an unbalanced panel of the form:

country year x y diff_x average_y initial_x 
A 1 xA1 yA1    
A 2 xA2 yA2 xA2-xA1 AVG(yA2:yA1) xA1 
A 3  yA3    
A 4  yA4    
A 5 xA5 yA5 xA5-xA2 AVG(yA5:yA2) xA2 
B 1  yB1    
B 2 xB2 yB2    
B 3  yB3    
B 4 xB4 yB4 xB4-xB2 AVG(yB4:YB2) xB2 
 
Basically, variable x has many missing values while y is available for all 
years.

I need to create 3 types of new variables (as in the last 3 columns of the 
table):

1) a variable that for each country will equal the difference between two 
consecutive available x values.(diff_x)
2) a variable that for each country will take the value the average of all y's 
available between  two consecutive available x values. (average_y)
3) a variable that for each country, for each available x takes the value of the 

previous observed x. (initial_x)

Any help would be much appreciated.
Thank you.
Laura



      

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