Newbie question: At what level does a covariate operate ?

[longrob604]

For example, section 5.3.5 of the centre for multilevel modeling online course, Module 5 practical, the covariate schtypeis added the the model. After adding, it has the subscript j instead of ij. But how does MLwiN know that it's a level 2 variable ? Where/how in the program is this set ? Or does MLwinN somehow work it out from the data ?

[ChrisCharlton]

MLwiN works out that it is a level 2 variable from the fact that its value is constant within each level 2 identifier. This can be demostrated by modifying the data prior to adding the variable to the model so that this is no longer the case. If you do this the subscript will then be ij instead of j.

[longrob604]

MLwiN works out that it is a level 2 variable from the fact that its value is constant within each level 2 identifier. This can be demostrated by modifying the data prior to adding the variable to the model so that this is no longer the case. If you do this the subscript will then be ij instead of j.

Hi Chris

Nice timing. I've just managed to work this out for myself, by doing exactly what you said. I was a bit surprised though, that it does this instantly, before the model is run.

Thanks
RL