My friend is working on material science and he published 3 papers in very good SCI index journals. In all papers he is first author and second is his supervisor and rest are co-authors like incharge of lab where test were conducted, teacher of his supervisor who is working in other university, some other scientist from USA who suggested the problem to his supervisor but was not involved in work in any other way and last co-author is student of his supervisor from same semester working on slightly different problem. In each of three papers the order and number of authors is same.
Now he is afraid of external examiner of his PhD thesis who may according to him might raise objection on inclusion of so many coauthors. All the papers were communicated by his supervisor so there was no chance for him to decide of his own. I told him that, this is a usual practice and nothing to worry about. Am I right ?
It is common for one or more graduate students to do most or all of the work leading to the paper/publication. If this is the case, their names should appear first. The boss/professor's name should appear last.