Zelig October 2009

zelig@lists.gking.harvard.edu

8 participants
10 discussions

by sayan dasgupta

Dear Zelig users I am using the R package Zelig for some tobit regression with robust standard errors. I have got R version 2.9.2 (2009-08-24) and Zelig Version: 3.4-5 when i do demo(robust) It ends like this way data(coalition) > # Fit the model with robust standard error > user.prompt() Press <return> to continue: > z.out3 <- zelig(Surv(duration, ciep12) ~ polar + numst2 + crisis, model = "weibull", data = coalition, cluster = "invest", robust = TRUE) *It is giving the following error *Error in rowsum.default(resid(fit, "dfbeta"), cluster) : 'x' must be numeric Please help where it is going wrong Thanks and Regards Sayan Dasgupta

14 years, 6 months

Re: SVM

by Kosuke Imai

Peter, We will put it on the to-do-list. Kosuke -- Department of Politics Princeton University http://imai.princeton.edu On Sun, 25 Oct 2009, peter jameson wrote: > Hi Kosuke! > I notice R has a Support Vector Machines implementation. > Any plans to implement this in Zelig? > > Cheers, Peter > - Zelig Mailing List, served by Harvard-MIT Data Center Send messages: zelig(a)lists.gking.harvard.edu [un]subscribe Options: http://lists.gking.harvard.edu/?info=zelig Zelig program information: http://gking.harvard.edu/zelig/

14 years, 6 months

num < 8

by Donald Braman

Dear Zelig Folk, For a few applications, I'd like to run a single simulation. I thought I might do this by setting num=1, but if I set num to anything less than 8, I get the following error: > Error in qi.polr(object[[1]], simpar = simpar, x = as.matrix(x), x1 = if > (!is.null(x1)) as.matrix(x1)) : subscript out of bounds Except when I set num to either 1 or 2, in which case I get the following error: Error in matrix(rnorm(p * n), n) : invalid 'ncol' value (too large or NA) It's not all that important to what I'm doing, but I'm curious if anyone knows why this happens or if there's anything that can be done about it. Cheers, Don

14 years, 6 months

quick question about error message

by Prashant

Hi, I'm trying to run matchit followed by zelig to calculate the ATT: After running z.out <- zelig(@@@), I get the following error message: Error in `[.data.frame`(d, , all.vars(as.expression(formula))) : undefined columns selected I'm not sure why I'm getting this error message--afterwards, I want to run: x.out1 <- setx(z.out1, data = match.data(m.outf, "treat"), cond = TRUE) s.out1 <- sim(z.out1, x = x.out1) Any help at all would be most appreciated! best, Prashant P.S. Specifically, I had run the following code: ps <- glm(Tr ~ female + urban + father_edu + mother_edu + siblings + hs_type_best + kuaiban + wangjie + sx_non_mil12 + I(age^2) + I(urban*age) + I(urban*mother_edu) + I(urban*sx_non_mil12) + I(female*sx_non_mil12) + I(urban*wangjie) + I(female*wangjie), family=binomial, data=my.data) X = cbind(age, female, urban, father_edu, mother_edu, siblings, hs_type_best, kuaiban, wangjie, sx_non_mil12, I(age^2), I(urban*age), I(urban*mother_edu), I(urban*sx_non_mil12), I(female*sx_non_mil12), I(urban*wangjie), I(female*wangjie), ps$fitted) m.outf <- matchit(Tr ~ X, data = rdmatchAC.lk12.range10, method = "genetic", ratio = 2, replace = TRUE, pop.size=1000, discard = "control") z.out1 <- zelig(Y1 ~ Tr + X + gk_score, model = "ls", data = match.data(m.outf, "control")) x.out1 <- setx(z.out1, data = match.data(m.outf, "treat"), cond = TRUE) s.out1 <- sim(z.out1, x = x.out1)

14 years, 6 months

odd qi$ev result

by Donald Braman

Even though there are only six possible values in my ologit esitmates, I get seven values in the qi$ev: > s.out$qi$ev 1 1 2 3 4 5 6 1 0.0037076 0.23622 0.14601 0.16821 0.18050 0.14410 0.12126 2 0.0033500 0.23162 0.11705 0.15862 0.20940 0.14789 0.13207 3 0.0020180 0.12770 0.08862 0.12422 0.18882 0.19016 0.27845 4 0.0022673 0.21746 0.12485 0.15439 0.19608 0.15260 0.15235 5 0.0031793 0.28474 0.14091 0.15632 0.18133 0.13101 0.10251 6 0.0024818 0.19614 0.11684 0.15278 0.22823 0.16162 0.14190 7 0.0039682 0.26576 0.13108 0.15688 0.19080 0.12478 0.12674 8 0.0015015 0.15490 0.09352 0.13356 0.23033 0.19183 0.19436 9 0.0027922 0.18692 0.11385 0.17334 0.20004 0.14274 0.18032 10 0.0032175 0.19282 0.12555 0.14715 0.20266 0.17849 0.15011 That's odd, isn't it? Why two columns of 1's? The same thing happens for qi$fd. I can send more code if need be, just curious if anyone has run into this before. Donald Braman phone: 413-628-1221 http://www.culturalcognition.net/braman/ http://ssrn.com/author=286206 http://www.law.gwu.edu/Faculty/profile.aspx?id=10123

14 years, 6 months

Re: [zelig] Analyzing subpopulations using Zelig

by Olivia Lau

Dear Fabricio, No, Zelig does not automate this. However, if you follow Thomas' suggestion in the survey design object input to Zelig, Zelig should be able to accommodate this since it passes all the *.survey models to Thomas' package. Best, Olivia 2009/10/10 Fabrício Mendes Fialho <fabriciofialho(a)gmail.com>: > Dear Olivia, > > Thanks for your message. > > Yes, if the sample is not stratified by religious groups (and this survey is > not), I will not have representative samples for these subsets. > > However, recently I read a Thomas Lumley's paper ("Analysing Survey Data in > R", R News 3(1), 2003) in which he states that: > > "Estimates on a subset of a survey require some care. Firstly, it is > important to ensure that the correct weight, cluster and stratum information > is kept matched to each observation. Secondly, it is not correct simply to > analyse a subset as if it were a designed survey of its own. The correct > analysis corresponds approximately to setting the weight to zero for > observations not in the subset. This is not how it is implemented, since > observations with zero weight still contribute to constraints in R functions > such as glm, and they still take up memory. Instead, the survey.design > object keeps track of how many clusters (PSUs) were originally present in > each stratum and svyCprod uses this to adjust the variance." > > According to this statement, subset analysis (for instance, comparing blacks > and whites, men and women, catholic and protestant, and so on) would be > possible since we keep all cases and survey design information while running > our analysis, just attributing zero weight to cases outside the subset of > interest. > > My question would be whether or not there is a Zelig command that automatize > this 'zero weighting process'. (but, of course, it is possible that my > question in fact does not make sense.) > > Thanks for your attention. > > Sincerely, > Fabricio > > 2009/10/9 Olivia Lau <olivia.lau(a)post.harvard.edu> >> >> Dear Fabricio, >> >> The answer depends on the original survey design. If the sample was >> stratified by each of the religious groups, then you can subset to the >> group or groups of interest, and analyze data from just those groups >> using logit.survey. If the sample was stratified using other >> background characteristics, then subsetting to the religious groups >> *and* employing survey weights will not create a representative >> sample. In this case, you have to refer to the survey design (which >> should be in the documentation of the particular survey) for guidance. >> If you know something about the alternative target populations (e.g., >> protestant, catholic, etc), then you could possibly reweight the data >> after subsetting. >> >> Yours, >> Olivia >> >> 2009/10/7 Fabrício Mendes Fialho <fabriciofialho(a)gmail.com>: >> > Hi there, >> > >> > I would like to know how may I obtain analysis for >> > subgroups/subpopulations >> > using Zelig. For instance, let suppose I am analyzing data on political >> > participation and religion, and I would like to estimate the effects of >> > political sofistication on electoral outcome. My data is from a complex >> > sample survey. Let also suppose respondents were classified in >> > "protestant", >> > "catholic", and "others". Considering theoretical issues, it would be >> > interesting to estimate the effect of political sofistication and >> > electoral >> > outcome just for the "protestant" group. >> > >> > How should I proceed to obtain this coefficient only for a subgroup (for >> > instance, "protestants")? How can I select this subgroup in my sample >> > when I >> > am running my analysis? For instance, I would like to run a >> > "logit.survey" >> > model, and I intend to include survey design information (PSU and >> > weights) >> > in my model. I would like to know how can I run analysis for this >> > subgroup >> > without just delete the other cases from my dataset since this procedure >> > would distort the original sample design. Should I just set the weight >> > to >> > zero for observations outside the subset of interest? Or is there other >> > way >> > to proceed? And if I intend to run a "logit" model (not a >> > "logit.survey"), >> > what should I do? >> > >> > I looked for directions about this in Zelig manual, but I did not find >> > instructions for this kind of analyses. >> > >> > Best regards, >> > >> > Fabricio >> > > > > > -- > > Fabrício Mendes Fialho > > web: sites.google.com/site/fabriciofialho/ > e-mail: fabriciofialho(a)gmail.com > - Zelig Mailing List, served by Harvard-MIT Data Center Send messages: zelig(a)lists.gking.harvard.edu [un]subscribe Options: http://lists.gking.harvard.edu/?info=zelig Zelig program information: http://gking.harvard.edu/zelig/

14 years, 6 months

Zelig and chopit

by Justin Marlowe

I'm having some trouble getting Zelig to simulate parameters from chopit model estimates. Zelig will reproduce the model estimates: > z.out <- zelig(f1, data = list(self = pmra, vign = pmra), model = "chopit") and set the parameters to their default values: > x.out <- setx(z.out, data = pmra) but when I try to run the simulations using the following code: > s.out <- sim(z.out, x = x.out) I get this error message: Error in UseMethod("vcov") : no applicable method for "vcov" Any suggestions? Thanks. -- Justin Marlowe jmarlowe(a)washington.edu Assistant Professor Daniel J. Evans School of Public Affairs Box 353055 Seattle, WA 98195-3055 - Zelig Mailing List, served by Harvard-MIT Data Center Send messages: zelig(a)lists.gking.harvard.edu [un]subscribe Options: http://lists.gking.harvard.edu/?info=zelig Zelig program information: http://gking.harvard.edu/zelig/

14 years, 6 months

Analyzing subpopulations using Zelig

by Fabr�cio Mendes Fialho

Hi there, I would like to know how may I obtain analysis for subgroups/subpopulations using Zelig. For instance, let suppose I am analyzing data on political participation and religion, and I would like to estimate the effects of political sofistication on electoral outcome. My data is from a complex sample survey. Let also suppose respondents were classified in "protestant", "catholic", and "others". Considering theoretical issues, it would be interesting to estimate the effect of political sofistication and electoral outcome just for the "protestant" group. How should I proceed to obtain this coefficient only for a subgroup (for instance, "protestants")? How can I select this subgroup in my sample when I am running my analysis? For instance, I would like to run a "logit.survey" model, and I intend to include survey design information (PSU and weights) in my model. I would like to know how can I run analysis for this subgroup without just delete the other cases from my dataset since this procedure would distort the original sample design. Should I just set the weight to zero for observations outside the subset of interest? Or is there other way to proceed? And if I intend to run a "logit" model (not a "logit.survey"), what should I do? I looked for directions about this in Zelig manual, but I did not find instructions for this kind of analyses. Best regards, Fabricio

14 years, 6 months

Zelig and matched data

by Ana Bracic

Dear all, I have a question about using Zelig on matched data. I have a matched dataset in Stata format (I used genetic matching with MatchIt), and I'd like to analyze it with Zelig. Can I simply load that dataset into R and run Zelig? Thank you, Ana

14 years, 7 months

adjusting *.survey regression model - which survey design information should I include?

by Fabr�cio Mendes Fialho

Hi Zelig developers and users, I am working with complex survey data; dataset is representative of a Brazilian metropolitan data. Sample is based on a three-level sampling: in the first stage, census tracts (CT) from the metropolitan area were randomly selected (with chances proportional to size); then, households were chosen from every previously selected census tract; finally, a respondent was randomly chosen from the adult members of the household. Initial sample design was designed for 1,270 cases, and the total of successfully completed interviews was 1,029. (survey response = 81%. not bad!) Dataset I am analyzing includes (1) post-stratification weights (to adjust proportionality due to survey non-response), (2) an “expansion factor” (a weight that equals the sample to the population, that is, it says approximately how many people in the population are represented in each sample case), and (3) census tract (indicating from which census tract each case was selected). Due to sample design, we have several cases from the same census tracts (99.9% of CTs provided from 5 to 20 cases; just one CT provided only one case). This way, it seems that the most appropriated regression models to analyze data from this sample might be the “.survey” ones (logit.survey, normal.survey, etc). All that explained, my question is: supposing a survey-weighted normal model like z.out <- zelig(Y ~ X1 + X2, model = "normal.survey", data = mydata) which information from survey design should I include? My first impression is that post-stratification weights (PSW) would correspond to “weights” input, the Census Tracts number would correspond to “ids” (since CTs are cluster from which each information was drawn). Can I include these two information in the same regression, obtaining something like z.out <- zelig(Y ~ X1 + X2, model = "normal.survey", ids = ~CT, weights = ~PSW, data = mydata)? Or can I include only one survey design information in a model? Or should I use other configuration? Thanks for all help, Fabricio M. Fialho -- Fabrício Mendes Fialho web: sites.google.com/site/fabriciofialho/ e-mail: fabriciofialho(a)gmail.com - Zelig Mailing List, served by Harvard-MIT Data Center Send messages: zelig(a)lists.gking.harvard.edu [un]subscribe Options: http://lists.gking.harvard.edu/?info=zelig Zelig program information: http://gking.harvard.edu/zelig/

14 years, 7 months

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Zelig October 2009