Hi everyone,
Several announcements:
1.) *We are changing rooms for lecture, starting Monday.* Lecture will be
held in CGIS N354 (the same room as the Thursday 6 PM section).
2.) A reminder that your memo offering suggestions on another group's
replication is due this Monday, April 10th at the beginning of lecture (2
PM EST for distance students). Details of what is expected are available
at the end of this handout:
http://www.courses.fas.harvard.edu/~gov2001/Assignments/repassign.pdf
3.) Problem Set 6 has now been posted and is due next Thursday, April
13th.
4.) The section handout and related R code for this week have now been
posted.
Have a great weekend.
Best,
Ian
Hi everyone,
I hope you had a good break and that your replications are going well.
Speaking of which, a reminder that the replication is due tomorrow at the
beginning of lecture (2 PM EST for distance students). Please make sure
you hand in all materials requested in the handout:
http://www.courses.fas.harvard.edu/~gov2001/Assignments/repassign.pdf
It is important that everyone hand in something tomorrow, as everyone's
work for the next phase depends on everybody else's.
Please also be on time for lecture and make sure you don't leave
without a CD containing another group's replication. (We will e-mail
distance students with their assigned replication shortly after lecture).
Don't hesitate to contact me if you have questions tonight or early
tomorrow.
Best,
Ian
Greetings,
My session on icegov1 was destroyed unexpectedly last night and I
don't know why. Did anyone else have a problem or is it my dumb luck?
Regards,
Sheldon
Hello!
I was wondering, does anyone know whether it is possible to create
variables dinamically, and also name and use them dinamically too? Say i
have a list like c("Sicilia","Russia","Mafialand"), and I want to create
a variable that has a human-comprehensible name, like the first few
letters from a list of country names.
would it be possible to dinamically create variables with names that
reflect the character strings, like "Russia.growth"? I am asking for
automation's sake, as I am tired of having to set ylab and xlab if i can
help it.
Thanks,
--
Serban Tanasa
Email: tanasa(a)fas.harvard.edu
Cell: 617-833-7847
Address: 513 Cabot Mail Center, Cambridge, MA 02138
For our replication project, Justin Grimmer and I have been exploring
missing data problems. We were given a data set by the authors that
was stripped of most identifiable information. Alas, it retains only
those variables necessary for the authors' OLS regressions, even
though it has a rich data history: it was produced by merging 1990
Census data with a detailed 1986 survey of municipalities. The
authors omitted any unique variable that would let us link back to the
original databases, a copy of which we have in our possession.
To identify the missing data points (the unit of analysis is
municipalities), we are trying to link the data table they used in
their regressions with the 1986 raw data or the 1990 Census. Lacking
a unique identifier, we have been unable to get an exact match, but we
have been trying to link on the following variables:
-Log of 1990 Census population--rounded to either 2 or 3 decimal pts.
(The problem here is that increasing precision captures rounding
errors between the two data sets, while decreasing precision leads to
too many false matches when we merge.) Because the authors rounded
the log of population to 3 (or so) decimal points, we get rounding
errors if we just try to exponentiate.
-Census region
-A variety of dummy variables for various survey responses. These
have been only somewhat useful since they are not a unique identifier.
-We think that the states are listed in alphabetical order in their
data table (based on the sequencing of regions) but we aren't sure how
to use this fact.
Linking on any combination of these produces either too few
identifiable matches or too many. We've been using the merge()
function in R. It seems to work okay but it is not good at identify
what's causing mismatches. We have gotten close to linking the 1990
Census data with the 1986 survey, but this only gets us to their first
step; it doesn't let us work backward to match with their table.
Has anyone on the list dealt with such a problem in the past? Any
suggestions are greatly appreciated. We're considering going back to
the authors, but we suspect they may not have what we need.
Thanks,
Clayton and Justin
Does anyone know how to set tolerance in R? The help files and a web search
have been fairly unhelpful. We have been having trouble with constrOptim
returning local optima unless you feed it initial parameters close to the
answers, and wanted to change the tolerance so that R finds it harder to
return an optimum.
Thanks
Sandip & Dan
