If a student's work has been substantially (>80%) revised, is s/he still qualified as the first author? The issue of authorship is often a thorny issue in academia, so I’d like to ask for your insight into the authorship in the following situation:

My advisee’s MA thesis is mainly and originally based on a new idea from me. We worked together to refine the idea and turned it into a thesis. I worked closely with him, spending 6 hours per week meeting with him to examine the collected data (he spent about 4 hours per week for data collection). Finally, he completed his thesis with a lot of work and graduated. After his graduation, I approached the student and asked him if he would be interested in publishing the study. He declined this offer mainly due to his availability and due to his work but appreciated this possibilities. Seeing the potential of the collected data, I decided to do this alone. 

To make the study publishable, I substantially revised more than 80 % of the student's work, using a different analysis method to recode the data and revamping the introduction, literature review, discussion, and conclusion sections. In other words, the revised paper, albeit being based on the student’s raw data set, is already substantially different from the student’s original work; the rationale is different and the focus is also different (just to appeal to the scope of the journal of our interest and the readership of the journal). 

The revised work was then submitted to a respected journal. I took care of all of the responses and revisions (three rounds of major revision + two rounds of minor revision), and the paper finally got accepted. Of course, I asked the student to read the paper and he liked/approved the paper.

I listed my student as the first author and myself as the corresponding author. But given my student’s contribution to this publication, is he qualified as the first author? Or should he be listed as the second author and myself as first author? What should I do so that I can strike a balance between the ethical code and the effort I have put to this paper?
There is no hard and fast rule about what exactly qualifies a person for first authorship, which is why it is so often a thorny issue (except in those disciplines where the convention is to always list people alphabetically).  It is also often highly dependent on the particulars of a given situation.  For example, I have had situations like this a number of times and in some cases have ended up keeping the student as first author and in other cases ended up replacing them.  

Accordingly, the principles that I would go by in making such a decision are, from most important to least important:


Did you previously make an agreement about authorship order?  If so, you should almost always respect that agreement.  Renegotiating, even if things have changed significantly, is likely to be coercive to the student given the difference of power between you.
How much work was the non-writing effort?  Advisors are often much, much better at writing than students, and 80% of the writing may be far less than 80% of the work that went into a paper, particularly if the advisor's writing focuses on the "supporting" material like references, introduction, discussion, etc.  If the student has put in a lot of hard work, especially if there has been significant intellectual work, in gathering the data, then I give the student first authorship even if I basically wrote the whole text.
Is the student interested in continuing in academia?  If authorship could be argued either way, and the student has any possible interest in continuing, it's generally better to put them first.  It's a gracious act promoting your proteges and you still gain recognition as the advisor on the paper.


In the end, it is likely that it will not be clear-cut exactly who should be first author.  Personally, I prefer to err in the direction of giving a student too much credit rather than too little, but others may choose otherwise.