Duplicate indicators- Expand function

[Maude Jodoin]

Hello,

Using the function "Expand 3" or "Expand 5", I would like to be able to distinguish the new observations created so that I can modify them independently of each other.

For example, I use the following line of code:

"expand 3 if num_quest==787 & year_start==1991, gen(dupindicator)"
*dupindicator= duplicate indicator

This creates one observation with dupindicator=0 and 2 observations with dupindicator=1.

How to create dupindicators with different values (ex. 0, 1, 2)?

[Nick Cox]

The expand command (not function) clones observations. Anything else to differentiate that must follow.

clear 
set obs 2 

gen x = _n 

expand 3 if x == 2, gen(triple)

bysort x (triple): gen new = _n - 1 if x == 2 

list, sepby(x)

     +--------------------+
     | x     triple   new |
     |--------------------|
  1. | 1   Original     . |
     |--------------------|
  2. | 2   Original     0 |
  3. | 2   Duplicat     1 |
  4. | 2   Duplicat     2 |
     +--------------------+

[Maude Jodoin]

Thank you!!