I noticed a table in a published paper showing odd ratios for subgroups followed by OR for the whole group. The OR of the total population was smaller than all of the ORs of the subgroups. My understanding was that the subgroups would have ORs that would vary from smaller to larger than the total population's OR. Should I suspect there is something wrong with the stats in the paper?
In statistics, does the odd ratio of the whole group for an outcome have to be within the odd ratios of subgroups for that outcome?
statistics;logistic regression