To assess the relationship between risk factors and outcomes, we have to do an assessment , there are several scales or tools. what is the best and most flexible tool can be use for this purpose?
If you already have the tool or the system to measure each risk factor and the outcomes, I would say regression analysis is the best tool to find the causality, i.e. if the assumption test are fulfilled.
There are several good recent books on causality (e.g., Pearl and Imbens & Rubin). As Essam says, the use of regression outside of an experimental setting needs to be done with care. FOr example, in their book on causality, Morgan and Winship state that this ``naive usage of regression modeling was blamed for nearly all the ills of sociology.'' (p. 13)