柠檬果 发表于 2012-12-13 16:10
想研究的问题是实施某项政策后,对因变量y的影响,在模型中,实施政策后x取值为1,实施政策前x取值为0,除x ...
不知道你的unit of analysis 是社么
如果是firn的话,
那是3-level random-effect modeling
level-1 firm
level-2 industry
level-3 year
i will use xtmixed to run this three-level model if DV is a continuous variable, or xtmelogit if DV is a binary one.
xtmixed y x1 x2 ||year: || industry: || firm:
if your unit of analysis is industry,
xtset industry year
xtreg y x1 x2, re
whether or not to include pannel variable(s) as your dummies depends on your research Q.
if research interest focuses on policy effects, i would not control for either time (year) or panel variable (industry). but I will explain variance componets in the multilevel model. it could tell us how much variance in each level.
i hardly see authors controled pannel variables as dummies in their panel analysis or multilevel model analysis, at least in my field, unless there is a spesiifc interest on effects of panel variable.