st: Missing values

[Beatrice Crozza <beatrice.crozza@gmail.com>]

Dear all,

I have just realised to have a problem with my database.
I need to generate the variable return from my prices. So  I did:
tsset time
gen lreturn= ln(price/l.price)
but the result is that there are 12 missing values.
This problem does not happen with Eviews, for example. What I did wrong?

Thank you very much

Bea
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