30 Nov
2002
30 Nov
'02
11:57 a.m.
Thanks, Nirmala. This does help. But what exactly is this "pooled" data that
we rbind together? Is it *only* the data from 1920 and 1918, 1930 and
1928, ..., 1990 and 1988, or should we somehow be including the data from 1912,
1914, 1916, 1922, ..., 1992? If we should be including the 2, 4, 6 -ending
years (Ryan's earlier email implied that maybe we should), I have no idea how
to go about this.
Anna
By "pooling" I think he means that we
combine all the years rather than
finding the incumbency effect for each election year. In other words,
instead of running the regression within the loop that merges current year
with lag year, rbind the merged data into a single dataframe within the
loop and then run the regression after you have the "pooled" data for all
the
years. I hope this helps.....
- Nirmala
30 Nov
30 Nov
12:29 p.m.
New subject: question re: 1(a)
Anna,
For this assignment I think we are only considering years 00 and 08. So
you can ignore 02, 04, and 06 for now.
In the loop, you will have something like....
this.year <- x...
last.year <- x...
y <- merge(this.year....
Then just insert something like
result <- rbind(result, y)
Be sure to define result as a dataframe() outside your "for" loop.
Make the function return the dataframe. Each row in the dataframe then
holds the merged data for one election year. This is your pooled data; you
can now run a regression on the whole thing.
I hope this helps. Do you know how to cut and paste code from the xemacs
window to the xterm window?
- Nirmala
12:42 p.m.
New subject: question re: 1(a)
Thanks, Nirmala. This is very clear. Your approach is the one I suspected I
ought to take, but didn't want to proceed without checking my understanding of
the assignment. Thanks for taking the time to explain it!
Anna
P.S. I don't know how to cut and paste from xemacs to xterm. I always run R
and the UNIX shell within xemacs, splitting my screen into three parts (my .tex
homework document is also open). If you want to set this up in order to cut
and paste easily using Ctrl-w and Ctrl-y, I'll explain more.
Quoting Nirmala Ravishankar <ravishan(a)fas.harvard.edu>du>:
Anna,
For this assignment I think we are only considering years 00 and 08. So
you can ignore 02, 04, and 06 for now.
In the loop, you will have something like....
this.year <- x...
last.year <- x...
y <- merge(this.year....
Then just insert something like
result <- rbind(result, y)
Be sure to define result as a dataframe() outside your "for" loop.
Make the function return the dataframe. Each row in the dataframe then
holds the merged data for one election year. This is your pooled data; you
can now run a regression on the whole thing.
I hope this helps. Do you know how to cut and paste code from the xemacs
window to the xterm window?
- Nirmala
--
Anna Lorien Nelson
Department of Government,
Harvard University
alnelson(a)fas.harvard.edu
8:16 p.m.
New subject: question re: 1(a)
Anna Lorien Nelson writes:
Thanks, Nirmala. This is very clear. Your approach
is the one I suspected I
ought to take, but didn't want to proceed without checking my understanding of
the assignment. Thanks for taking the time to explain it!
My thanks to Nirmala as well. Her answers are the correct ones. If
these problem sets are ever used again, I will try to ensure that the
appropriate corrections are made. As noted before, we encourage
everyone to both ask questions on the list and to answer them. Other
classes reward class participation. We don't. We reward list
participation.
"pooling" is a generic term, mostly referring to the practice of
combining observations that come from different time periods. We
"pool" when we place voting results for 1920, 1930 and so on in one
vector and then try to explain that vector (by using it as the
dependent variable in the regression).
Note that, when we do so, we are making some (strong?) assumptions
about exchangability.
Dave
--
David Kane
Lecturer in Government
617-563-0122
dkane(a)latte.harvard.edu
7832
days inactive
7833
days old
gov1000-list@lists.fas.harvard.edu
3 comments
3 participants
participants (3)
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Anna Lorien Nelson -
Dave Kane -
Nirmala Ravishankar