I am performing a meta-analysis. I have a subgroup made only of 2 studies and they show opposite results. The 1st has excellent outcomes the 2nd very bad ones.
Is it true that I am not allowed to compute the data from these two (different) studies under a random-effect model? I have been told that it is methodologically not correct to perform a meta-analysis of 2 studies with such opposite results.
They suggested me to report the raw data from these studies separately (without an overall outcome calculated by a random-effect model). Any suggestion? Or any place where I can find the explanation about this point?