Gov2001 April 2006

gov2001@lists.gking.harvard.edu

36 participants
56 discussions

[gov2001-l] Genetic Matching

by ghumphr＠fas.harvard.edu

Hi, I had another look over GenMatch. It looks to me as though it is nothing more than a stochastic beam search for Euclidean distance metrics. Surely I must be missing something. Geoff

18 years

[gov2001-l] help

by jfvargas＠fas.harvard.edu

Hi list, a quick question, In some funtion I am trying to implement, R is telling me that "m must be positive", and m is defined: k<-exp(par[2]) betas<-par[3:7] lambda<-exp(-(x%*%betas)) m<-k/lambda can anyone think why I am getting negative m's? Thanks, Juan

18 years

[gov2001-l] extension .tgz

by jfvargas＠fas.harvard.edu

Hi, I downloaded the library 'rmutil' and wnat to have a look at its documentation, which is on the website of the author under the extension .tgz. Does anyone know how to open and view such files? Thanks, Juan

18 years

[gov2001-l] The Convex Hull

by ghumphr＠fas.harvard.edu

If any of this doesn't make sense, please let me know. The _convex hull_ is the set of points at the border of the _convex set_ (which is a set of space and does not appear to be defined in the current version of the Oxford English dictionary). The convex hull occupies no space, but contains all of the points.

18 years

[gov2001-l] Reminder: Dan's Office Hours FRIDAY This Week

by dhopkins＠fas.harvard.edu

Hi All, Just a quick reminder that my office hours will be Friday from 4 - 6 PM in the main concourse-level computer lab in CGIS North (and not today). My regular Wednesday office hours will resume next week. Best, Dan ---- Ph.D. Student Department of Government Harvard University Tutor, Currier House dhopkins(a)fas.harvard.edu http://www.danhopkins.org

18 years

[gov2001-l] pset 7 1(a)

by dhopkins＠fas.harvard.edu

Hi Holger, I'm "cc"ing the list since that's an entirely reasonable pair of questions. Yes, we mean comparing the world where we see these same observations with all treatment indicators set to 0 to the world where all treatment indicators are set to 1. And by original sample, we mean three separate samples: the mail sample (assigned to treatment of one mailing and controls), the door sample (assigned to treatment of one door-knock and controls), and the phone sample (assigned to one phone call vs. controls). Best, Dan ---- Ph.D. Student Department of Government Harvard University Tutor, Currier House dhopkins(a)fas.harvard.edu http://www.danhopkins.org On Mon, 17 Apr 2006, Holger Lutz Kern wrote: > Hi Dan and Ian, > > I have a question about ps 7 (a). I > estimated the ITT for each of the three > treatments, but am having trouble > understanding what you want us to do > next. Specifically, what do you mean by > the first difference in this case? > Comparing a world in which no one was > assigned to the treatment to a world in > which everyone was? And does whole > sample refer to the original sample with > multiple treatments or the "door", > "mail", "phone" subsamples that we > constructed? > > best, > Holger > > > -- > Holger Lutz Kern > Graduate Student > Department of Government > Cornell University > > Institute for Quantitative Social Science > Harvard University > 1737 Cambridge Street N350 > Cambridge, MA 02138 > > www.people.cornell.edu/pages/hlk23 > >

18 years

[gov2001-l] COST first differences (3->4)

by ghumphr＠fas.harvard.edu

Hi, Considering that no one specified 4 for COST (and trying to pull out an absolute scale is ridiculous in this situation), we should not calculate first differences between COST=3 and COST=4, correct? Geoff

18 years

[gov2001-l] problem (e): y_i =0 when y_i^* >0?

by takagi＠fas.harvard.edu

Hi all, The question says that "y_i = 1 when y_i^* > 0 and 0 otherwise." Could you tell me if it is correct? I feel that it might be "y_i = 0 when y_i^* > 0 and 1 otherwise" rather than "y_i = 1 when y_i^* > 0 and 0 otherwise" in order to approximates the probit model because the observation mechanism for the probit model is is y_i = 0 if y_i^* > \tau and 1 otherwise where y_i is observed realization , y_i^* is unobserved variable, and \tau is the threshold parameter. Thanks, Yuki

18 years

[gov2001-l] ps 6 (f): estimating the optimal number of degrees of freedom

by hlk23＠cornell.edu

Hi all, for ps 6 (f), I'm trying to estimate the optimal number of degrees of freedom. The problem is that my estimates are quite dependent on the starting value that I give optim. I've tried several methods but they all produce unstable results even after setting maxit=10000 so that convergence takes place. Does anyone have any suggestions what to do? Thanks, Holger -- Holger Lutz Kern Graduate Student Department of Government Cornell University Institute for Quantitative Social Science Harvard University 1737 Cambridge Street N350 Cambridge, MA 02138 www.people.cornell.edu/pages/hlk23

18 years

[gov2001-l] Re: Zelig for part f?

by dhopkins＠fas.harvard.edu

Hi Jacqueline, Yes, it is fine if you use Zelig for part (f). Best, Dan ---- Ph.D. Student Department of Government Harvard University Tutor, Currier House dhopkins(a)fas.harvard.edu http://www.danhopkins.org On Fri, 14 Apr 2006, Jacqueline Chattopadhyay wrote: > Hi Dan and Ian, > I know that we can't rely on Zelig for PS 6, except to check answers, but > does this mean that Zelig-generated graphs are also banned for part > (f)--comparing models and explaining which one to choose? > Thanks, > Jacqueline >

18 years

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Gov2001 April 2006