I have been approached by an international student about doing a PhD with me. As an MSc student in his home country he has published 3 articles in pay-to-publish venues, that are known to have little peer-review process, with his supervisor as second/senior author. These articles are not particularly good and likely would not have been publishable in more traditional venues.
I am struggling with how to evaluate these articles and the candidate. Should I simple ignore the place/type of publication and evaluate the work on its own? Can articles in pay-to-publish places really be fairly evaluated? I am worried that changing his behavior will be difficult. I don't want to accept a student whose goal is to publish things in pay-to-publish places.