st: Period specific coefficient for individual effects

[hwiig <henrik.wiig@econ.uio.no>]

Hi!

I want to estimate whether some observed individuals characteristics have 
led to a higher wage increase in an otherwise fixed (unobserved) individual 
characteristic panel data model, i.e. the level form model is as follows:

Y_it = a + a_i + b_t * Z_i + c * X_it

i = individual
t = periode
Y=Income
Z= dummy for male
X=Hours of labour

This implies the following model of changes:

(*) ch_Y_i = aa + (ch_b)*Z_i + c * ch_X_i

aa=constant that reflects constant period effects
ch_Y_i = change in income
ch_b = change in the effect of the observed characteristic of the individual
ch_X_i = change in hours worked

I can of course construct all ch_variables and run it as simple OLS 
regression with Stata command "reg". Meanwhile, I guess it easier (and more 
secure) to run some kind of fixed effect "xtreg" model in a "long" data set 
(years ordered in columns). How do I do this? What is the commands I should 
use?

Hope anyone can help me!

Cheers, Henrik


Henrik Wiig
Department of Economics
University of Oslo
PO Box 1095 Blindern, N-0317 Oslo, Norway
Eilert Sundts hus, 12th floor, Moltke Moes vei 31
Telephone: 22 85 51 35
Fax: 22 85 50 35
E-mail: henrik.wiig@econ.uio.no
Private telephone: 22 55 24 84
Mobile telephone: 47 75 75 09
http://folk.uio.no/hwiig/


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