I have a small sample size of participants (n=8) who were enrolled in a study to evaluate the change in one of the urine metabolites over time. The concentration of this metabolite in the urine was measured in three different occasions (baseline or time zero, after three months and then after six months.
I would like to study the change in this metabolite concentration over time. I am uncertain about the utility of the mixed effect model in such a small sample size, especially since there were concerns raised in the literature about the accuracy of this type of analysis.
Snijders, T.A.B. & Bosker, R.J. (2012). Multilevel Analysis: An Introduction to Basic and Advanced Multilevel Modeling. London: Sage Publishers. Hox, J. (2010). Multilevel Analysis: Techniques and Applications. New York: Routledge.
I would like to inquire about the correct method to be used in such case. Is the mixed effect model still the best approach? Is ANOVA a better choice for the difference over time in such a small sample size?