[R-sig-ME] Question on hierarchical nature and data format using lmer

[Bernard Liew]

Dear Community,

Thank you first for the help. My question pertains to a research design as follow:

200 students in total from 4 schools, undergoing different clinical placements in a semester. There are 5 different plausible clinical placements. This means some students have zero placements, others can have a maximum of three, with any placement combinations. Two out of three clinical placements are restricted to some schools. So some clinical placements are nested within schools, others are crossed across schools.

The response variable is an ordinal measure Likert scale of "sharing". The predictors are school and placement.

Qn to be answered: Does different school and clinical placement alter a student's degree of sharing?

Problem 1: data format

The traditional way to format the data is the long "tidy" method. However, because placements are not unique to an individual, how best should one format the data?

Solution 1 ( I think): make the placement variable into a wide format, so instead of one placement predictor, I now have five different placement predictors. This then appears to change the research question? Is there another solution?

Kind regards,
Bernard


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