1. Could anybody give me a detailed explanation about why is inappropriate not to use a constant in a logistic regression model? Could you provide me any example about how that would bias the results?

2. Is there any exception for this rule? For example, small/large sample sizes, low/high number of independent variables included in the model, 50%,<50%,>50% incidence of the outcome in the sample, or anything else?

3. I have got strikingly different results according to whether I include the constant in the model. Our hypothesis is favored by not including the constant. Is that somehow expected?

I really appreciate your help guys,

Looking forward to learn with you,

Best regards