CODEWITHSUNDEEP
stata
ChinG
ChinG

Reputation: 125

How can I generate a new variable that is the difference in value of the same variable across different years?

I have a dataset in Stata of the following form: 

 Individual Year  VariableX VariableY 
   1        2013   x11        y11      
   2        2013   x12        y12
   .         .      .          .
   N        2013   x1N        y1N
   1        2014   x21        y21
   2        2014   x22        y22 
   .         .      .          .
   N        2014   x2N        y2N

As can be seen above, the dataset is sorted by year. I now wish to create another variable Z, the change in X by Year, that is, for individual 1 for instance, her value for this variable should be x21 - x11 (her value of x in year 2014 - her value of x in year 2014).

Upvotes: 0

Views: 429

Answers (1)

Galax
Galax

Reputation: 1431

When working with panel data, you can tell Stata how your data is arranged with:

xtset individual year

One way of accessing the the one year lagged value is by using the L. operator:

generate z = x - L.x

Other than that you should probably read up on manipulating panel data in Stata.

Upvotes: 1

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