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/