I have a question about SEM and would like to learn some solutions.

Suppose I use three indicators to measure one's concern about the environment (x1 x2 x3).

Then I will have three individual level predictors (income education age) and two country level predictors (GDP CO2).

I have run the following model

gsem (Concern -> x1 x2 x3) (Concern <- income education age M1[GDP] M2[CO2])

However, Stata does not run and said

"invalid path specification; Concern may not be the destination of a path from M1[GDP]"

How may I revise the code and fix the problem?

Thanks.