What is the appropriate statistical test to assess a variable over different points of time without intervention and how we can determine sample size?

07 July 2016 1 7K Report

Dear colleagues:

What is the most appropriate statistical test to assess a variable (e.g. patients' knowledge) over different points of time without intervention, and how we can determine the sample size?

Georgios Kotsakis

Hi Izzeddin, I am not sure what you refer to as "no intervention". If you are referring to a single cohort without group stratification, then you could use a GEE model with a time variable as an independent variable. For the sample size you would need to have information on the correlation patterns between measurements over time. It is a bit tricky; see here for an overview, and good luck:

http://www.hindawi.com/journals/as/2014/303728/

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