Usually I will not provide any recommendation or reference letters except for some very specific cases (see below). You should also not mention me as a reference in your application documents without my explicit allowance.

In my opinion such letters are typically an unwarrantable waste of resources, especially time. It is a deplorable custom that many institutions require or appreciate such letters. In 95% of the cases I cannot add any valuable information which couldn’t be obtained also from other application documents such like academic transcript of records. This is because most students who ask for such a letter, I do not know very well, perhaps from some classes. But then a reference letter is not more than verbosely re-iterating the information that the person is a „good student“, thus creating a lot of redundancy. If such a letter should make sense (a) I must have to add interesting information which cannot be obtained from other documents, (b) the student must be significantly above average (otherwise I could „recommend“ any student).

There are few cases where I really can add some important information for the reader which cannot easily be obtained from other documents. This is when the candidate has written a thesis under my supervision. Then I can say something about the self-dependence, open-mindedness, creativity, research capabilities etc., so that writing such a recommendation letter makes sense – given that I really appreciated the supervised thesis. Especially graduates who want to make a PhD should have a (very) good overall study performance, and a (very) good thesis which shows promising research capabilities. Recommendation letters for PhD programs require detailed knowledge about the candidate’s skills, performance, research skills which I do not have if not having supervised the master thesis. Therefore I am not competent to assess the research abilities of the candidate.

Summing up, I will write recommendation letters for students and postgraduates only in case of joint research papers, or when I supervised their Master thesis which should have a very good grade. Then I can honestly recommend somebody. In all other cases I will not write such letters.