First, where does the focus group segment of your work fit into the mixed methods design as a whole, and what is the goal for the focus groups? Second, due to the qualitative research subjective nature, this field does not generally use the term validation, so can you say more about why you are interested in this issue?

Hello Professor Morgan

You said in your answer to a question... deductive analysis is based on pre-defined codes... now my question is... if I use a tool that is implemented qualitatively (because based on specific questions and indicators that of course produce free answers), but in the end it will be scored quantitatively based on a Likert scale for the quantitative part of my study, this means the quantitative part is a deductive study? Because the questions based on structured interviews will be coded by the coder.

Starting with a qualitative method to generate the content for a survey instrument is known as an "exploratory sequential" design in mixed methods research (qual --> QUAN). For more information on this and other mixed methods designs, I suggest you consult Creswell and Plano-Clark, Designing and Conducting Mixed Methods.