question about small number group unit. NEED HELP! THANKS!
Posted: Fri Nov 24, 2017 4:15 pm
Hi everyone, I have questions on 2-level multi-model with small number level-2 unit.
I am trying to study educational issue in two different areas A and B. In area A, I collected data from 20 schools with 229 individuals, and in area B, there is only data from 17 schools with 119 invididuals. I am constructing two multi-model for each area. Considering the limitation of data, I just built random slope model without adding cross level variances, and beyesian method is used.
However, the model for area A can run smoothly, and problems occurs in the model for area B. for some (not all) independent variables, when I want to see if the slope changes for different schools, it doesn't converge.
My questions:
Is there anyone could explain the above non-converge issue? Is it because the small number of schools in model? if so, why model for area A can run (only 3 schools more);
Besides, I found that even though I didn't add any level-two independents, why the model shows that variance at school-level still drop as well?
Many thanks for any help!!!
I am trying to study educational issue in two different areas A and B. In area A, I collected data from 20 schools with 229 individuals, and in area B, there is only data from 17 schools with 119 invididuals. I am constructing two multi-model for each area. Considering the limitation of data, I just built random slope model without adding cross level variances, and beyesian method is used.
However, the model for area A can run smoothly, and problems occurs in the model for area B. for some (not all) independent variables, when I want to see if the slope changes for different schools, it doesn't converge.
My questions:
Is there anyone could explain the above non-converge issue? Is it because the small number of schools in model? if so, why model for area A can run (only 3 schools more);
Besides, I found that even though I didn't add any level-two independents, why the model shows that variance at school-level still drop as well?
Many thanks for any help!!!