When I attempt to supply a long variable list as part of the formula in zelig(), I am getting an error: Error in parse(file, n, text, prompt) : syntax error in "cbind( id(presvote, "2") ~ whitesouth + relft + soph2 + pid + age + ," Removing one variable, however, solves the problem: Changing the variables involved seems to make no difference; it is apparently just the length of the variable list that matters. Incidentally, I can run the model fine using vglm (through VGAM) directly. traceback() says: 12: parse(text = x) 11: eval(parse(text = x)[[1]]) 10: formula(eval(parse(text = x)[[1]])) 9: switch(mode(x), "NULL" = structure(NULL, class = "formula"), character = formula(eval(parse(text = x)[[1]])), call = eval(x), stop("invalid formula")) 8: formula.default(object, env = baseenv()) 7: formula(object, env = baseenv()) 6: as.formula(paste(lhs, rhs)) 5: cmvglm(formula, mf$model, mf$ones, ndim, data, fact) 4: zelig2mlogit(as.factor(presvote) ~ whitesouth + relft + soph2 + pid + age + unionhh + black + married + female, "mlogit", list(weight = c(1.7249, 0.4922, 1.1457, ....)), 1) 3: do.call(fn1, list(formula, model, dat, N, ...)) 2: zelig.default(as.factor(presvote) ~ whitesouth + relft + soph2 + pid + age + unionhh + black + married + female, model = "mlogit", data = smallframe) 1: zelig(as.factor(presvote) ~ whitesouth + relft + soph2 + pid + age + unionhh + black + married + female, model = "mlogit", data = smallframe) Thanks in advance, Chris -- Christopher N. Lawrence <c.n.lawrence(a)gmail.com> - Zelig Mailing List, served by Harvard-MIT Data Center Send messages: zelig(a)latte.harvard.edu [un]subscribe Options: http://lists.hmdc.harvard.edu/?info=zelig Zelig program information: http://gking.harvard.edu/zelig/