3-levels & time
Posted: Tue Jun 24, 2014 9:30 am
Hi,
I'm modelling transition to birth amongst European women and have a little difficulty to interpret the random part of my model.
I got observations (or waves if you like) on the first level, individuals (women) on the second and country on the third. I was looking for some examples of interpretation in the literature but so far I haven't found anything satisfactory. So I'm primarily using Leckie & Charlton's article to try to understand as I am using Runmlwin in STATA. What really puts me off is the interpretation of time on the first level. I'm not really fussed by it since my main motivation behind using panel data was to deal with the fact that birth is quite a rare event and also that my sample sizes are not that amazing. So basically I just want to control for the fact that the observations are not independent of each other and want to focus primarily on the level 2 outcomes. Can I do that? Also how big a problem in this case can be the fact that I have on average 1.8 observations?
Anyway, I've run an empty model and this is what I've got.
intercept = -2.0828, predicted probability = 0.1108
level-2 variance = 0.5862 => VPC = 0.1512
level-3 variance = 0.1267 => VPC = 0.0371
I would crudely interpret it as the probability of giving birth is about 11%, about 15% of the variance in transition to birth is between women and about 4% is between countries. Does it therefore mean that the differences in transition to birth is due to differences in women's characteristics rather than country-specific characteristics? It might be a stretch but does it also mean that the differences in birth occurrence may be due to compositional effects rather than country-specific characteristics? And what happens with the time? Does it relate only to the time-varient women's characteristics or does it need special interpretation?
As you can see I'm a little bit confused...Thank you.
Alzbeta
I'm modelling transition to birth amongst European women and have a little difficulty to interpret the random part of my model.
I got observations (or waves if you like) on the first level, individuals (women) on the second and country on the third. I was looking for some examples of interpretation in the literature but so far I haven't found anything satisfactory. So I'm primarily using Leckie & Charlton's article to try to understand as I am using Runmlwin in STATA. What really puts me off is the interpretation of time on the first level. I'm not really fussed by it since my main motivation behind using panel data was to deal with the fact that birth is quite a rare event and also that my sample sizes are not that amazing. So basically I just want to control for the fact that the observations are not independent of each other and want to focus primarily on the level 2 outcomes. Can I do that? Also how big a problem in this case can be the fact that I have on average 1.8 observations?
Anyway, I've run an empty model and this is what I've got.
intercept = -2.0828, predicted probability = 0.1108
level-2 variance = 0.5862 => VPC = 0.1512
level-3 variance = 0.1267 => VPC = 0.0371
I would crudely interpret it as the probability of giving birth is about 11%, about 15% of the variance in transition to birth is between women and about 4% is between countries. Does it therefore mean that the differences in transition to birth is due to differences in women's characteristics rather than country-specific characteristics? It might be a stretch but does it also mean that the differences in birth occurrence may be due to compositional effects rather than country-specific characteristics? And what happens with the time? Does it relate only to the time-varient women's characteristics or does it need special interpretation?
As you can see I'm a little bit confused...Thank you.
Alzbeta