CODEWITHSUNDEEP
stata
Micha
Micha

Reputation: 23

Generate difference between observations as new variable in Stata

I am trying to get the difference between the natural logarithms of two consecutive observations for a set of variables.

My approach is as follows 

. gen abandon_qry_ln = ln(abandon_qry) - ln(abandon_qry) [_n-1]

But I get the error weights not allowed.

Any idea what could be the issue?

Upvotes: 1

Views: 16588

Answers (1)

Nick Cox
Nick Cox

Reputation: 37358

You could work with 

gen difference = ln(abandon_qry) - ln(abandon_qry[_n-1])

or 

gen ln_abandon_qry = ln(abandon_qry) 
gen difference = ln_abandon_qry - ln_abandon_qry[_n-1]

You were trying to subscript an expression. You may subscript a variable or a matrix in Stata, but not in general an expression.

Upvotes: 3

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