I am an agricultural researcher and grad student who repeated the same experiment three years in a row. The experiment is a randomized complete block design with field as the block (i.e. it was replicated by location instead of multiple blocks at one location). I have two independent variables (treatment and time) and five dependent variables (height, width, color, yield, and flavor). Each year, data was collected over time, so I am using PROC mixed with repeated measures. My question is how do I account for the 'year' component in my analysis? Technically, I conducted three separate experiments (albeit the same experiment), once a year in 2019, 2020, and 2021. However, the point of repeating the experiment over three years is to control for differences by production season and demonstrate that the results are consistent year after year. I am referencing both my statistics and SAS texts, and everything talks about collecting data over time (in the case of repeated measures) and not what to do with your analysis when the whole experiment was repeated multiple times. Any insight is appreciated. Thanks!
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