Hi guys! I am new in Stan and I am little confused about ordinal regression.Here are some questions:

**1]** I was trying to fit for my data an ordered logistic regression (only fixed effects) with brm and stan_polr function and after many trials I figured out that they produce the same results (using as argument the cumulative “logit” and family=“logistic” respectively). Which is the difference between these functions then? Maybe that in brms someone can add random effects or other facilities to his formula?

**2]** The brm function is the respective of lrm (library rms) from classical statistics like stan_polr which is respective with polr from MASS package?

**3]** For the two different versions (brms and rstanarm) which is the form of the model? I mean the form of the model is this logit(p_j)=b_{0j}+(b_{1} X_1+...+b_k X_k) or logit(p_j)=b_{0j}-(b_{1} X_1+...+b_k X_k) ?

Because in MASS package the - is used and the lrm library the +.

**4]** Finally, how can I change the baseline category in ordered in stan?In multinomial logistic the 1st level is used instead of ordered where the last level is used as baseline. I want to adjust it so that I have the baseline in 1st level my baseline .

Thank you for your time!