I am conducting a fixed-effects analysis with a three-wave panel data set. I am regressing wage on participation in an educational training program. However, I am also interested if the Impact of participation changes dependent on the voluntariness of participation. So: xtreg wage participation##voluntary covariates, fe vce (cluster id).
This is my Problem: Only if someone participates in treatment, they are asked if they are participating voluntarily or are forced to do so. So it lookes s.th. like this:
*I have excluded everyone who already participated in wave 1, because I cannot calculate a before-and-after estimator for them.
I think that a fixed-effects analysis needs a transition from zero to one in any case, also for an interaction term and that this is why, if I try to conduct an analysis, Stata tells me that I have "no observations". I looked it up, and there definitely are cases, so it is not a problem of too many missings. However, I do not have any transition in my data from voluntary== 0 to voluntary == 1.
I thought about changing the missings of the "voluntary"-variable prior to the participation into zero's.
sort id wave
replace voluntary = 0 if voluntary[_n+1] !=.
So it looks like this:
But I am unsure whether that might wreck my control group (though I wouldn't know why, since I just change the missings prior to participation) or if there any other problems with it.
I am very interested in your feedback. Or maybe you have any other idea on how to tackle that problem? Thank you very much in advance!
This is my Problem: Only if someone participates in treatment, they are asked if they are participating voluntarily or are forced to do so. So it lookes s.th. like this:
| id | wave | Treatment (yes=1) | voluntary (yes=1) |
| 1 | 1 | 0* | (missing) |
| 1 | 2 | 1 | 1 |
| 1 | 3 | 1 | 1 |
| 2 | 1 | 0 | (missing) |
| 2 | 2 | 0 | (missing) |
| 2 | 3 | 1 | 0 |
I think that a fixed-effects analysis needs a transition from zero to one in any case, also for an interaction term and that this is why, if I try to conduct an analysis, Stata tells me that I have "no observations". I looked it up, and there definitely are cases, so it is not a problem of too many missings. However, I do not have any transition in my data from voluntary== 0 to voluntary == 1.
I thought about changing the missings of the "voluntary"-variable prior to the participation into zero's.
sort id wave
replace voluntary = 0 if voluntary[_n+1] !=.
So it looks like this:
| id | wave | Treatment (yes=1) | voluntary (yes=1) | old variable | voluntary (yes=1) | new variable |
| 1 | 1 | 0 | (missing) | 0 |
| 1 | 2 | 1 | 1 | 1 |
| 1 | 3 | 1 | 1 | 1 |
| 2 | 1 | 0 | (missing) | (missing) |
| 2 | 2 | 0 | (missing) | 0 |
| 2 | 3 | 1 | 1 | 0 |
I am very interested in your feedback. Or maybe you have any other idea on how to tackle that problem? Thank you very much in advance!