Hi there, I hope someone might be able to help me out with some coding for proc glimmix. I'm not as familiar with coding r-side random effects and have been banging my head against this problem for too long so I hope that this forum might be able to offer some suggestions. I'll try to give a detailed description of the study design first. This is a study dealing with bird counts in Canada. Our first step was to randomly select 9 41-km square "landscapes" that fell into three "treatments" (the landscapes were dominated by different vegetation types) and each treatment was replicated three times (so there were three 41-km square landscapes that were treatment 1, three landscapes that were treatment 2, and three that were treatment 3), for a total of 9 different 41-km square landscapes. Within these landscapes we surveyed for birds in accessible parcels of land using a point count method (i.e., stand at one spot and listen for birds). This study was done over 2 years and each point count location was surveyed once per year. There were approximately 170 point count locations. Many of our species were either present or absent (binary dependent variable) at each point count and we are interested in exmaining how bird presence or absence varies in response to various vegetation parameters (vegetation height, etc.), as well as some other parameters of interest (landscape metrics, etc.). But given the repeated measures I am having some difficulty coding the glimmix script. This is what I've come up with so far and I'd be interested in getting some feedback. I hope my descriptions of the study design helps. proc glimmix data=XX ; class Year Land_Type LandID; model occ(event='1')=vht /dist=binary link=logit solution; random landid(Land_type); random Year/Subject=PCSite type=ar(1) residual; run; A collaborator suggested that we incldue the individual "landscape" nested within treatment effect (the landid is simply an indentification number given to each individual landscape irrespective of treatment) and land_type is the treatment type (3 possible treatments), but I am stuck on how to code the repeated measures of the same site between years. Any suggestions would be extremely helpful! Please if I did not present enough information let me know. Thanks for any help/suggestions! Ryan
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