Hi, sorry for another post.

I need help creating variable W1 (shown below). The idea is, for each coder during a spell, he/she may get an I3=1. When this happens, for each coder during each spell, I want the W1 to equal 1 and then remain as 1 until the end of the spell.

For example, take coder 101417. He/she has two spells (1 and 2). During spell 1, the coder doesn't witness an I3=1 at all, so W1 stays as 0 throughout that spell. During spell 2 for that same coder, he/she does witness an I3=1 in the second instance. Therefore for that coder during that spell, the W1 variable needs to be 0 in the first instance (as of that time, the coder hadn't witnessed a I3=1 yet during that spell) and then W1 needs to be 1 in the second instance (because it is then that the coder did witness a I3=1 during that spell) and then W1 needs to be 1 in the third instance (because at that time, during that spell, the coder had already witnessed a I3=1, which happened in the second instance).

Any help would be greatly appreciated.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
coder_id dateno I3 spell W1
101287  58 0 1 0
101287  59 1 2 1
101287  60 0 2 1
101287  77 0 3 0
101287  80 0 4 0
101417   1 0 1 0
101417 109 0 1 0
101417 112 0 1 0
101417 113 0 1 0
101417 115 0 1 0
101417 116 0 1 0
101417 117 0 1 0
101417 135 0 1 0
101417 200 0 2 0
101417 209 1 2 1
101417 344 0 2 1
101446  22 0 1 0
101447  21 0 1 0
101447  37 0 1 0
101447  90 0 2 0
101447  91 1 2 1
101447 314 0 2 1
end