Hi, I am trying to fit a model to my ordered categorical data. I have been using : Bayesian ordinal regression with random effects using brms to help, as well as https://journals.sagepub.com/doi/full/10.1177/2515245918823199 to help. I am very new to bayesian models, so I am aware that I have pro…

There are multiple ways to approach this, but my response will be centered around one of your opening statements: “I am very new to Bayesian models.” Given that you have a background in the social sciences, my guess is you’re familiar with the normal distribution and with z-scores (i.e., values fro…

Thank you so much for your answer, working through it slowly! Just to check, I get an error when I run your code on my actual data, which is Error in cumulative(probit) : object 'probit' not found the variables are the same, a factor and ordered factor (lifeExp), I’m not sure where I’m going wrong …

You probably just need to put probit into quotes :-) family = cumulative("probit")

No, tried that! Gives : "Error in UseMethod("cumulative") : no applicable method for 'cumulative' applied to an object of class "character" When I use Solomon’s answer on the data I provided, it works. But when I use it on my own data of a similar structure, I get the error

Are your categorical variables coded as factors in the data frame? – I’m clutching at straws here.

Yes they are, but I’ve solved it: It works if I put brmsfamily("cumulative","probit"), So there must be a package in the project I’m using, that isn’t in the project I set up the data for this question in :)

thank you for clutching at straws with me :)

A follow up question, would it make sense to change the reference category and run it again?

Sure. Putting the whole ordinal issue aside, code your data so that you are using a meaningful reference category.

Setting priors and interpreting ordered logistic model

Interfaces brms

GabriellaS-K December 30, 2021, 5:40pm 11

Hi ! I’ve added a new question/follow up on interpreting: Question about interpreting ordinal cumulative model with probit link

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Setting priors and interpreting ordered logistic model

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