How should the weights be treated? If they are multiple observation weights (a weight of "3" is shorthand for 3 subjects) that leads to a different likelihood than sampling weights ("3" means to give this one subject more influence). The clogit command can't read your mind and so has chosen not to make a guess. Also, please do not post in html. As you see below it leads to a mangled message. Terry Therneau On 12/22/2015 05:00 AM, r-help-request at r-project.org wrote:> Merry Christmas everyone: > I have the following data(mydat) and would like to fit a conditional logistic regression model considering "weights". > id? case?exposure?? weights > 1?????1?????????1????????? 2 > 1?????0?????????0????????? 2 > 2?????1?????????1????????? 2 > 2?????0?????????0????????? 2 > 3?????1?????????1????????? 1 > 3?????0?????????0????????? 1 > 4?????1?????????0???????? ?2 > 4?????0?????????1????????? 2 ?The R function"clogit" is for such purposes but it ignores weights.?I tried function"mclogit" instead which seems that it considers the weights option:##############################################################options(scipen=999)library(mclogit)# create the above data frameid????????? = c(1,1,2,2,3,3,4,4)case????? =?c(1,0,1,0,1,0,1,0)exposure = c(1,0,1,0,1,0,0,1)weights? = c(2,2,2,2,1,1,2,2)(mydata??= data.frame(id,case,exposure,weights)) fit??????= mclogit(cbind(case,id) ~ exposure,weights=weights, data=mydata)summary(fit)###################################################################### > The answer,however,?doesn't seem to be?correct. Could anyone?pleaseprovides me with some solution to this??Thanks in advance,Keramat Nourijelyani,PhD?? > > [[alternative HTML version deleted]] >