Matthias, This is so very helpful! Thank you so much for exposing me to this. Seems like exactly what I was looking for. Best regards, Asaf -- View this message in context: http://r.789695.n4.nabble.com/Two-way-Random-Effects-with-unbalanced-data-tp4647795p4648995.html Sent from the R help mailing list archive at Nabble.com.