Should I use reflective or formative construct?

[Marsha Sabrina]

Dear All,

I have an observed firm performance as dependent variable (i.e. performance measured by ROA, ROE, Tobin's Q, and market to book ratio). Then the independent variable are three type of ownership structure (foreign, managerial, and state ownership). The mediation variable is independent commisioner.
So i am confused how should i model this observed?. Should it be a formative construct or a reflective construct?. Thanks