I am fitting 3-level linear models to a data set containing about 60,000
test scores nested in 17,000 students nested in 1,000 schools. I am
considering introducing a 4th level (teachers or classrooms), which neither
HLM software nor SAS PROC MIXED can handle. Can NLME fit a 4-level model to
a data set of this size?
If so, let me ask about another capability. In my data, the level 1 error
variance is known from psychometric analysis. I would like to set this
variance component to this known value before the other variance components
are estimated. SAS PROC MIXED has a PARMS command which allows me to do
this. Is there anything comparable in NLME?
Best wishes,
Paul von Hippel
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