hello everybody solved the problem with summary, now I have another one
eg I estimate > try.op <- polr( > as.ordered(sod.sit.ec.fam) ~ > log(y) + > log(1 + nfiglimin) + > log(1 + nfiglimagg) + > log(ncomp - nfiglitot) + > eta + > I(eta^2) + > uomo + > elem + > laurea + > saluteno + > extra > , > data = dfscale, > method = "probit", > Hess = T > ) now I've putted Hess=T in order to perform a summary on the estimate. I missed this option last time > try.op > Call: > polr(formula = as.ordered(sod.sit.ec.fam) ~ log(y) + log(1 + > nfiglimin) + log(1 + nfiglimagg) + log(ncomp - nfiglitot) + > eta + I(eta^2) + uomo + elem + laurea + saluteno + extra, > data = dfscale, Hess = T, method = "probit") > Coefficients: > log(y) log(1 + nfiglimin) > 0.76200482 -0.17791762 > log(1 + nfiglimagg) log(ncomp - nfiglitot) > -0.33306775 -0.22487707 > eta I(eta^2) > -0.03177126 0.00030204 > uomomaschio elem > -0.02737021 0.05259243 > laurea saluteno > 0.19143184 -0.23067414 > extra > -0.27810954 > Intercepts: > 0|1 1|2 2|3 3|4 4|5 5|6 6|7 7|8 > 5.22647 5.42504 5.76277 6.03395 6.31709 6.88459 7.27907 7.82273 > 8|9 9|10 > 8.50723 8.83105 > Residual Deviance: 16325.59 > AIC: 16367.59 > (58 observations deleted due to missingness) unfortunately when I do > summary(try.op) I get > summary(try.op) > Errore in svd(X) : valori infiniti o mancanti in 'x' ... infinite or missing values. If I exclude I(eta^2) from the estimation I can do summaries: but I need also I(eta^2) in order to compare this model with the same specification estimated with Ols Can you please help me or give me an hint? If it can be useful, i hereby put an estimation with stata's oprobit function (varnames are a little bit different) > . oprobit lz2_1 ly lnfiglimin lnfiglimagg lnadulti eta eta2 uomo elem laurea > saluteno extra > Iteration 0: log likelihood = -7877.9258 > Iteration 1: log likelihood = -7633.4001 > Iteration 2: log likelihood = -7633.3455 > Ordered probit estimates Number of obs = 3747 > LR chi2(11) = 489.16 > Prob > chi2 = 0.0000 > Log likelihood = -7633.3455 Pseudo R2 = 0.0310 > ------------------------------------------------------------------------------ > lz2_1 | Coef. Std. Err. z P>|z| [95% Conf. Interval] > -------------+---------------------------------------------------------------- > ly | .6998939 .0369605 18.94 0.000 .6274526 .7723351 > lnfiglimin | -.1177089 .0467595 -2.52 0.012 -.209356 -.0260619 > lnfiglimagg | -.3195756 .0475709 -6.72 0.000 -.4128128 -.2263383 > lnadulti | -.2644527 .0588268 -4.50 0.000 -.379751 -.1491544 > eta | -.0245736 .0048287 -5.09 0.000 -.0340376 -.0151096 > eta2 | .000236 .0000485 4.87 0.000 .0001409 .000331 > uomo | -.0226491 .03348 -0.68 0.499 -.0882686 .0429705 > elem | -.0072757 .0524754 -0.14 0.890 -.1101257 .0955743 > laurea | .119691 .0527058 2.27 0.023 .0163895 .2229925 > saluteno | -.1299579 .0724971 -1.79 0.073 -.2720495 .0121337 > extra | -.3077715 .0963483 -3.19 0.001 -.4966107 -.1189323 > -------------+---------------------------------------------------------------- > _cut1 | 4.403418 .3797857 (Ancillary parameters) > _cut2 | 5.018157 .3793925 > _cut3 | 5.372828 .3796109 > _cut4 | 5.705886 .3800993 > _cut5 | 6.314861 .3814847 > _cut6 | 6.723659 .3826026 > _cut7 | 7.278588 .3842792 > _cut8 | 7.963981 .386254 > _cut9 | 8.288727 .3871242 > ------------------------------------------------------------------------------ > . log close > log: z:/home/luca/stata_oprob.log > log type: text > closed on: 15 Mar 2008, 10:13:50 > -------------------------------------------------------------------------------------------------------- thank you Luca -- Luca Braglia, aka Bragliozzo http://bragliozzo.altervista.org ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.