And here’s a thing in response to your comment above, Sandra. Say you are examining a thesis, composed of papers that have been published, and you have serious problems with one paper – or worse, more than one – that is in it. (No examination, BTW, is a ‘rubber stamp’; thesis examination is not the same thing as peer review for publication – although it is a related skill). Are you going to ask for a rewrite? What if the student wasn’t the main author on that paper, and you think there are serious weaknesses in it, in the light of the whole thesis? Should it be removed and replaced with something more suitable? That could be a lot of work you are asking the student to undertake, but you may feel that the thesis isn’t passable without that. I have in my thesis a book chapter, which is the text of a conference presentation I did at the end of my first year of enrolment. It hasn’t been peer reviewed by anyone (unless you count the book editors who simply picked it up on a google search and through it fitted their theme), and I did a lot morter work on it before I put some of it in my thesis – having had it published at the beginning of my thinking process didn’t mean it was suitable for the final document.
The introductory or summary chapters of a thesis by publication should be written independently by the student. They should include an extensive annotated bibliography or literature review , placing the scope and results of the articles in the wider context of current state of the international research. They constitute a comprehensive summary of the appended papers, and should clarify the contribution of the doctoral student if the papers are written by several authors. They should not provide new results, but may provide synthesis of new conclusions by combining results from several of the papers. They may supplement the articles with a motivation of the chosen scope, research problems, objectives and methods, and a strengthening of the theoretical framework, analysis and conclusions, since the extent of the articles normally does not allow this kind of longer discussions.