# Questions tagged [polr]

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

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1 vote
321 views

### How to interpret interaction effect in ordinal (logistic) regression?

I ran an ordinal regression in R with the polr function from the MASS package as described in this tutorial, which is very good. However, the tutorial does not ...
• 252
113 views

### Calculating confidence intervals for coefficients in ordinal logistic regression

I've fitted an ordinal logistic regression model in R using MASS::polr and I am looking to compute confidence intervals for the fitted coefficients. Here is the (...
60 views

### Prediction intervals using predict.polr vs predict

I am a little puzzled by this - hope you will give this a shot! I am looking for a way to get prediction intervals from an ordered logit model (polr()). The ...
1 vote
49 views

### MIxed Model Ordinal Regression Drops Random Intercepts

Please could you help me? I have been trying for quite some time to fit a mixed model with multiple binary and continuous predictors and an ordinal dependent variable. Subject ID defines the random ...
10 views

### Probability to belong in a class in a Proportional Odds Logistic Regression

I'm having trouble understanding how the probability of belonging to each class is being calculated. Appreciate it if someone could help me out! Assuming the dependent variable with 3 ordinal classes (...
84 views

### How to do ordinal logistic regression (OLR) on survey data with categorical answers?

I am trying to learn how to use r to perform an ordinal logistic regression, in order to look for correlation between survey questions with categorical answers and another question asking about level ...
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21 views

### Ordinary logistic regression correctly applied/ is the model correct to answer my question [duplicate]

I am trying to model the following and would be happy about input/if its correct. I want to compute a model that checks on differences between Statuses between data sets plotted here on the graph: The ...
425 views

### Interpreting ordinal regression output in R polr()

I ran an ordinal regression in R using polr(), and have checked the proportional odds assumptions with brant() from the brant package. I am very new to ordinal regression and I am a bit confused about ...
• 93
1 vote
465 views

### Multicollinearity for ordered logistic regression

How is multicollinearity calcuated for an ordered logistic regression if R^2 is not determined for this type of regression? Because the formula for vif says: 1/(1-R^2) In R the looking up ...
• 65
50 views

### Can the s.e. be used to identify heteroskedasticity for an ordered logit regression?

The title of this post actually says what I want to ask about. To detect heteroksedasticity for an ordered logit regression using the polr function in the MASS package in R can the standard error from ...
• 65
1 vote
890 views

### Example of a three-way interaction plot in R

Is this an example of interaction plot? However, in the bottom of the article it is wrtitten, that it's not a 3-way-interaction (link to article). How should I understooth it? If it's not a 3-way-...
• 65
1 vote
275 views

### What can cause violation of the proportional odds assumption?

What can the reasons be that the assumption of proportional odds / assumption of parallel regression lines is not met? By using MASS::polr in R, I tried to run ...
• 65
27 views

### Can the coefficients in ordered logit be interpreted or is it necessary to determine exp()? [duplicate]

When estimating an ordered logit using MASS::polr is it then possible or a good idea to interpret the coefficient from the summary output or is it necessary to determine the exp() and use the ...
• 65
44 views

### What is your recommendation for using ordered logit regression?

I'm estimated the effect of discrepancy of working hours on satisfaction of life, so I modeled an ordered logit regression using MASS:polr for my thesis. I created ...
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156 views

### R polr's zeta equivalent in glm?

I am a grad student with little experience with R. I am wondering if there is an equivalent of polr's zeta in glm. For a part of ...
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54 views

### Different results from polr depending on whether categorical variable is encoded as string or number

Our aim is to find out whether the general self-efficacy (GSE), as measured by the "New General Self-efficacy Scale" (1-10), changes in participants after the completion of a specific task ...
164 views

### A couple of polr Issues for ordinal regression with ordinal independent variables

I am having trouble using polr for a ordinal regression because I also have ordinal independent variables. Looking online it looks like I should either convert them to categorical dummy variables or ...
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97 views

### test proportional odds assumption of lagged variable in ordered logistic regression

I want to estimate transition probabilities between different disease states called "Remission", "Mild" and "moderate/severe". I have an unbalanced panel of 250 patients ...
• 39
786 views

### Plot predict probabilities wiht ggplot2 and brms [closed]

I'm a PhD student in psycholinguistics and I'm having trouble in modeling some ordinal data. I have an ordinal response (completely disagree, disagree, neutral, agree, completely agree) and two ...
3k views

### Can someone explain what the Brant test in R does?

I’m using R to run proportional odds models through the polr function in the MASS package. I want to see if the proportional ...
1 vote
3k views

### Ordinal logistic regression interpretation of polr summary in R [duplicate]

I am trying to interpret the coefficients for the polr model. Where each predictor has three levels, Dissatisfied, Neutral, and Satisfied. Dissatisfied is the baseline. The dependent variable has the ...
1 vote
392 views

### Ordinal logistic regression (polr in R): DV wrong level order

I am (trying) to conduct an ordinal logistic regression for the first time using the polr function in r. I seem to be encountering a problem with the order of my levels of my DV. My DV should have ...
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1 vote
29 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 ...
• 111
681 views

### Random effects for ordinal logistic regression? [duplicate]

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 ...
145 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 ...
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1 vote
124 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 ...
• 135
142 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, ...
• 608
1 vote
1k 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. ...
599 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 ...
• 570
39k 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 ...
1 vote
354 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%) ...
1 vote
619 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 ...
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9k 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 (...
• 101
421 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: ...
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1 vote
348 views

### Is there an R package to check the proportional odds assumpion? [closed]

is there an R package/function to implement the parallel slope test given a clm (ordinal package) or polr (MASS) package?
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1 vote