You gave detailed information on mixed methods, quantitative, and qualitative research and it was informative. I would disagree with you that quantitative research would be the best, because you would be missing the observational aspect for your research study. You used stratified random sampling to collect data on men who use methamphetamine, because everyone does not consume this substance (Hesse-Biber, 2010).
Your discussion post sounds like the mixed method design you are referring to is sequential explanatory design, because it collects the quantitative data first and the qualitative data second. There are advantages to using mixed methods in research studies and one of them is the results may include both observations and statistical analyses. Therefore, the results are validated within the study. Using both approaches in one study provides additional evidence and support for the findings. Would you agree?
A different design method you could use would be the concurrent triangulation design. This method is used to confirm, cross-validate, or corroborate findings, by concurrently collecting the qualitative and quantitative data in one phase. The data for this method is analyzed separately and then compared and/or combined (Johnson, Onwuegbuzie, & Turner, 2007).
Your ethical issues are valid. However, because this is a study about the effects of methamphetamine consumption my ethical issue would be avoiding harm to participants and offering inducements for research (APA, 2010). The reason I point out these ethical concerns because the research involves an illegal substance that could be fatal to the participants. You do not want to entice participants to illegally use drugs just to be in a research study. Good post!!
American Psychological Association. (2010). Ethical principles of psychologists and code of conduct: Including 2010 amendments. Retrieved from http://www.apa.org/ethics/code/index.aspx.
Hesse-Biber, S. N. (2010). Mixed methods research: Merging theory with practice. New York, NY: Guilford Press.
Johnson, R. B., Onwuegbuzie, A. J., & Turner, L. A. (2007). Toward a definition of mixed methods research. Journal of mixed methods research, 1(2), 112-133. Retrieved from http://www.cirt.gcu.edu