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# Re: st: questions about Fixed Effect models

 From Syed Basher To statalist@hsphsun2.harvard.edu Subject Re: st: questions about Fixed Effect models Date Fri, 25 Feb 2011 14:55:11 -0800 (PST)

```Hi,

Since you're new to panel data (and therefore FE models), you may find the
http://dss.princeton.edu/training/Panel101.pdf

Syed Basher

----- Original Message ----
From: Stata Email <mystataemail@gmail.com>
To: statalist@hsphsun2.harvard.edu
Sent: Fri, February 25, 2011 11:05:28 PM
Subject: st: questions about Fixed Effect models

Dear Statalist members

I am new in panel data and I am working with fixed effect models. I
would like to confirm if I am doing the right thing

When working with panel data, the data set is such that we have
information about individuals i and we observe these individuals
through different time periods t. My questions are

1) Which part of the Stata output shows me that the fixed effect is important?
2) What does it mean exactly R-sq within? R-sq between?
3) If I run a fixed effect model, the sigma-u is the std dev of the
residuals inside (within) each group of individuals i. So a higher
number means that I have more variability inside each group?
4) sigma-e show the std dev of the residuals after excluding the
variability inside each group i? If that is true, a higher number
means that I have a big variability among groups i and therefore the
fixed effect is important?

Now let me explain what kind of data set I have. I have a data set
with the proficiency level of students, followed for 5 years. But I
know who is the teacher for every student in all 5 years. I want to
calculate a teacher fixed effect (and I control for the proficiency
level from the previous year instead of having a student fixed
effect). My other questions are

5) My individuals i here are the teachers and, instead of having a
time t, I have students s with the same teacher
6) All within statistic will refer the the differences among students
with the same teacher?

I really appreciate any comment
Isabel

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