If you are interested in using mixed methods, you will need to have a clear research design specifying how you will both combine the two methods and integrate their results. I suggest that you consult the textbook by Creswell and Plano-Clark to gain insight into this process.

Askar Mambetaliev I am not convinced that a mixed methods approach would require collecting data at multiple sites. For example, I think it would be possible to execute a sequential explanatory design by conducting a QUAN survey at a single site, followed by qual interviews at the same site to help understand the quantitative results.