# Questions tagged [polr]

polr refers to a R function in package MASS for ordered logistic or probit regression.

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### What to do if an ordinal logistic regression with continuous predictors has a cell in the expected frequency table that is <1

Thank you in advance for your help. I am running an ordinal logistic regression with a DV of 5 levels and two continuous predictor variables. So, for goodness of fit, I need to run Lipsitz or the ...
20 views

### What is a good algorithm for measuring the relationship between numerical input variables and ordered categorial output?

I have a dataset with 50 numerical input variables and 1 output column. The output is categorical and ordered. I want to describe the relationship between the numerical variables and the categorial ...
22 views

### McFadden's pseudo-$R^2$ based on reduced instead of intercept-only model?

McFadden's pseudo-$R^2$ is defined as difference in the log-likelihoods of the full and intercept-only model $1 -(loglik(full)/(null))$ Given a multiple regression scenario (ordinal regression in ...
40 views

### Random effects for ordinal logistic regression?

I am relatively new to R. I am currently using R studio to run an ordinal logistic regression for some research. Initially I just ran the ordinal logistic regression using R's polr function, I didn't ...
43 views

### proportional odds logistic Regression with function polr() in R

I know this topic has come up quite some times but I am still not completely able to wrap my head around some interpretation issues. So I am using the function polr() from the MASS package in R. I ...
54 views

### margins() on polr() model

I'm trying to work with polr instead of clm because with my large data set and a complicated model it requires a very large amount of RAM (300gb)... Margins works, withouot yielding SE, z, p-values ...
31 views

### Interpreting interaction odds ratios in ordinal regression

I have run an ordinal regression in R using polr from the MASS package. I'm trying to interpret an interaction. Both predictors are categorical. Here is an example: Predicting success in the job ...
101 views

### ordered logistic regression marginal probabilities hit ceiling

I'm running an ordered logistic regression with 3 classes, and I am able to predict the probability of each observation belonging to each class. For some reason one class' probabilities (top40) never ...
104 views

### Ordered probit model prediction: why highest probabilities and not number of thresholds exceeded?

I'm running ordered probit regression models with polr in R. This question states that for prediction, ...
450 views

### Ordinal Logistic Regression with Polr: Compare multiple treatments

Let's say I have information about three stages of cancer (Stage 1, Stage 2, Stage 3) and three treatment groups. Now I'd like to compare if the odds ratio for all of these three groups are different. ...
441 views

### Interpreting results of multinomial model using polr

I am trying to correctly interpret and plot the effects of a multinomial model fit in R. The data and script are here for reproducing the problem. The multinomial variable describes different ...
17k views

### How to use ordinal logistic regression with random effects?

In my study I will be measuring workload with several metrics. With heart-rate variability (HRV), electrodermal activity (EDA) and with a subjective scale (IWS). After normalization the IWS has three ...
287 views

### Ordered Logistic Regression GWAS

I am attempting to do an ordered logistic regression in R on SNP matrixes (presence absence matrix 1 or 0) with three outcomes (1,2,3). I am having an issue of 0 p-values when low numbers (<5%) ...
283 views

### How should I determine degrees of freedom for t-test in ordinal regression?

I consider a proportional odds (ordinal regression) model, as described in Agresti (2002) and estimated by R base package ...
6k views

### Checking the proportional odds assumption holds in an ordinal logistic regression using polr function

I have used the ‘polr’ function in the MASS package to run an ordinal logistic regression for an ordinal categorical response variable with 15 continuous explanatory variables. I have used the code (...
372 views

### difficulties evaluating if a ordinal multnomial model fitted with polr (in Rstudio) can be used for predicting over new data

I'm getting very different output when i perform a multinomial ordinal model depending on wether I scale or not my data first. Anyone could tell me why? Here are the results with raw data: ...