How to calculate variables with one year lag

[Saleh sharmah]

Dear members
I’m trying to creat new variable_ sales growth calculated as ( current year sales - last year sales)/ last year sales.

kindly, can anyone provide me with the code in calculating the above wanted variable?

thanks in advance

[Carlo Lazzaro]

Saleh:
you may want to try something along the following lines:

. use "https://www.stata-press.com/data/r17/nlswork.dta"
(National Longitudinal Survey of Young Women, 14-24 years old in 1968)

. tsset idcode year

Panel variable: idcode (unbalanced)
 Time variable: year, 68 to 88, but with gaps
         Delta: 1 unit

. g wanted=L1.ln_wage

. list ln_wage wanted year if idcode==1

       +----------------------------+
       |  ln_wage     wanted   year |
       |----------------------------|
    1. | 1.451214          .     70 |
    2. |  1.02862   1.451214     71 |
    3. | 1.589977    1.02862     72 |
    4. | 1.780273   1.589977     73 |
    5. | 1.777012          .     75 |
       |----------------------------|
    6. | 1.778681          .     77 |
    7. | 2.493976   1.778681     78 |
    8. | 2.551715          .     80 |
    9. | 2.420261          .     83 |
   10. | 2.614172          .     85 |
       |----------------------------|
   11. | 2.536374          .     87 |
   12. | 2.462927   2.536374     88 |
       +----------------------------+

.

[William Lisowski]

Triplicate post also answered at https://www.statalist.org/forums/for...ons-with-a-lag