Hi all, I am trying to perform an ordinal regression using proportional odds model. First I would like to test whether the assumption of proportional odds is supported by the data. I got the following error message when I try to fit one of the relevant models. Can anyone give some suggestions on how to fix this. Thank you. Hanna fit2 <- vglm(PLANHORIZON ~ factor(TotalCompanion) + factor(NumTrips)+factor(Numnight)+factor(FMWEBSITE)+factor(OTHERWEB)+factor(BROCHU) + +factor(TRAAGENT) + factor(WOM) + factor(AAA) + factor(GUIDEBOOK) + factor(ADVERTISE) + factor(NEWSPAPER) + factor(INFOOTHER) + + ExpTotal + factor(AGE) + factor(CHILD) + factor(INCOME), + family=cumulative(parallel=F), data=two) Error in if (any(smallmu <- (mu * (1 - mu) < double.eps))) { : missing value where TRUE/FALSE needed In addition: Warning messages: 1: In Deviance.categorical.data.vgam(mu = mu, y = y, w = w, residuals residuals, : fitted values close to 0 or 1 2: In Deviance.categorical.data.vgam(mu = mu, y = y, w = w, residuals residuals, : fitted values close to 0 or 1 [[alternative HTML version deleted]]