Beta regression 0/1 duplicates

Question

I noticed that we have three threads which appear to address the exact same topic.

Can someone with expertise in this area make a recommendation of which questions should be closed as a duplicate of which target?

• Beta regression of proportion data including 1 and 0
• Dealing with 0,1 values in a beta regression
• Why exactly can't beta regression deal with 0s and 1s in the response variable?

(We may have more than three threads on this topic, these just happened to turn up in an unrelated search.)

Answer 1

I would not prefer to make them duplicates but instead make their differences more clear. (and in addition add more obvious links to the different questions for the interested reader that wants to read related questions)

One of the questions ask why the values 0 and 1 are not allowed. Another question asks how to deal with values 0 and 1 if somebody likes to do beta regression. And yet another questions asks for alternative models for beta regression (which might overlap with the 'how to deal' question).

• So my question is instead of modifying the data, why not modify the model? Dealing with 0,1 values in a beta regression
• I have read elsewhere that theoretically the beta distribution should be able to handle values of 0 or 1 but I do not know how to handle this in R.I have seen some people add 0.001 to the zeros and take 0.001 from the ones, but I am not sure this is a good idea? Beta regression of proportion data including 1 and 0
• My question is: which property of beta distribution prevents beta regression from dealing with exact 0s and 1s, and why? Why exactly can't beta regression deal with 0s and 1s in the response variable?