Hi all, Iain, Thank you for your answer. There seems to be a delay, sometimes up to a day, in time at which I receive emails from gov2001-I-Digest. There is another thing that either Maya or you could help me with. Following today's class and Gary's recent (2009) notes on CEM that I found online, I am writing my own code for CEM in R. We still haven't covered the R code for it, but it makes sense to try it out on our classmates' work before I hand my assignment in on Thursday. I use in order to drop the treatment variable (nucass) and the dependent variable (acquire) from the analysis. That is the code from Gary's notes. I do that so to prevent matching on those two variables. However, I get this error report: Error in which(t1 > 0 & t2 > 0) : binary operation on non-conformable arrays In addition: Warning messages: 1: In reduce.var(data[[i]], breaks[[vnames[i]]]) : NAs introduced by coercion 2: In reduce.var(data[[i]], breaks[[vnames[i]]]) : NAs introduced by coercion 3: In min(x) : no non-missing arguments to min; returning Inf 4: In max(x) : no non-missing arguments to max; returning -Inf Could you tell me interpretation of this error report, so I could run the command properly. I appreciate your help. Nino Malekovic MPA Candidate, Class 2011 Harvard Kennedy School ________________________________________ From: gov2001-l-bounces at lists.fas.harvard.edu [gov2001-l-bounces at lists.fas.harvard.edu] On Behalf Of gov2001-l-request at lists.fas.harvard.edu [gov2001-l-request at lists.fas.harvard.edu] Sent: Monday, March 29, 2010 12:00 PM To: gov2001-l at lists.fas.harvard.edu Subject: gov2001-l Digest, Vol 56, Issue 50 Send gov2001-l mailing list submissions to gov2001-l at lists.fas.harvard.edu To subscribe or unsubscribe via the World Wide Web, visit http://lists.fas.harvard.edu/mailman/listinfo/gov2001-l or, via email, send a message with subject or body 'help' to gov2001-l-request at lists.fas.harvard.edu You can reach the person managing the list at gov2001-l-owner at lists.fas.harvard.edu When replying, please edit your Subject line so it is more specific than "Re: Contents of gov2001-l digest..." Today's Topics: 1. Re: gov2001-l Digest, Vol 56, Issue 49 (Malekovic, Nino) 2. Re: gov2001-l Digest, Vol 56, Issue 49 (Iain Osgood) 3. Re: gov2001-l Digest, Vol 56, Issue 49 (Yousuf) ---------------------------------------------------------------------- Message: 1 Date: Sun, 28 Mar 2010 16:41:16 -0400 From: "Malekovic, Nino" <nino_malekovic at hks11.harvard.edu> Subject: Re: [gov2001] gov2001-l Digest, Vol 56, Issue 49 To: "gov2001-l at lists.fas.harvard.edu" <gov2001-l at lists.fas.harvard.edu> Message-ID: <5D4D069369CE1A4984610C041D23C9AF012952155636 at MAIL.hks.internal> Content-Type: text/plain; charset="us-ascii" Hi, I guess my question is for our TF-s. To what extent we have to help our colleagues improve their papers? Specifically, should we focus on improving their contribution (until now that was mainly replication of original data analysis), or should we also draw their attention to what seem questionable in author's original analysis? Any help is appreciated. Nino Malekovic MPA Candidate, Class 2011 Harvard Kennedy School ________________________________________ From: gov2001-l-bounces at lists.fas.harvard.edu [gov2001-l-bounces at lists.fas.harvard.edu] On Behalf Of gov2001-l-request at lists.fas.harvard.edu [gov2001-l-request at lists.fas.harvard.edu] Sent: Saturday, March 27, 2010 12:00 PM To: gov2001-l at lists.fas.harvard.edu Subject: gov2001-l Digest, Vol 56, Issue 49 Send gov2001-l mailing list submissions to gov2001-l at lists.fas.harvard.edu To subscribe or unsubscribe via the World Wide Web, visit http://lists.fas.harvard.edu/mailman/listinfo/gov2001-l or, via email, send a message with subject or body 'help' to gov2001-l-request at lists.fas.harvard.edu You can reach the person managing the list at gov2001-l-owner at lists.fas.harvard.edu When replying, please edit your Subject line so it is more specific than "Re: Contents of gov2001-l digest..." Today's Topics: 1. logit clustered SEs (Lin, Eric) ---------------------------------------------------------------------- Message: 1 Date: Fri, 26 Mar 2010 20:46:06 -0400 From: "Lin, Eric" <elin at hbs.edu> Subject: [gov2001] logit clustered SEs To: Class List for Gov 2001/E-2001 <gov2001-l at lists.fas.harvard.edu> Message-ID: <75A246F5-57C4-4DCE-B134-DA0B18718805 at hbs.edu> Content-Type: text/plain; charset="us-ascii" one follow up: Like lmr() from the Design package, `gee' doesn't like it when you give it dummies that create collinearity. run glm() first, and see what it dropped to avoid collinearity. Then, drop those from your specification. Run this using gee(), and use the id=`` for specifying what you want to cluster on. -- ERIC LIN Technology and Operations Management Harvard Business School Boston, MA 02163 elin at hbs.edu