Research on the effects of domestic violence

I’m working on research on the effects of domestic violence and having a hard time fixing these questions. Please will need your help with the details of these questions.

What are some ways you could increase the internal validity of the effects of domestic violence?

What is the importance of external validity for your study of the effects of domestic violence?

Is internal validity or external validity more important for your study of the effects of domestic violence?

What do you find most difficult about the idea of validity?

What aspects of evaluating it or integrating it into research design are the most challenging and why?