Short version:
I am fairly new to multilevel modelling and would like to avoid it. My question is basically if I can leave it aside given the nature of my data and the goals of my analysis.
My explanatory variables are all constant within the clusters. However, my binary dependent variable does vary within the clusters (but not within all of them). Do I need a multilevel model here? Or should I decide this based on theoretical considerations on the independence of the outcomes within the clustering?
Additional information:
The data:
The observations are legal acts. My dependent variable is 1/0 indicating one of the two types of legal act I am interested in. These legal acts are clustered through so called "parent acts", i.e. legal acts that multiple (or single) acts refer to. All my explanatory variables are on the level of these "parent acts".
My goal:
So several observations have the same "parent act" and therefore the exact same values for their explanatory variables. However, the observations refering to the same "parent act" can differ in their outcome (1/0). I basically want to use the characteristics of the "parent act" to estimate the likelihood of one outcome over the other.
My question:
Given this data structure, do I need to use a multilevel model that takes into account the clustering in the different "parent acts". I am unsure because, except of the dependent variable, all variables are on this "level 2" (if this is the correct term here). Since I expect that certain characteristics of a "parent act" will make one of the outcomes more likely, the observations referring to the same "parent act" should not be independent. On the other hand, there are quite few "parent acts" to which only one of both types (1/0) refers to.
Although my results are in line with my theoretical expectations, my intuition tells me not to trust them. Please tell me if I'm wrong here. Thank you!