“If you have worked on a collaborative dissertation, a potential employer might struggle to see whether you really are an independent thinker or could you read a lead a research project,” says Ortega.
There is another matter to wrestle with — the fact that half of science Ph D graduates in the United States are choosing careers outside of academia, according to the National Science Foundation's 2014 Survey of Earned Doctorates.
Almost all involve a written thesis, but those come in many forms.
In the United Kingdom, they are usually monographs, long explanations of a student's work; in Scandinavia, science students typically top-and-tail a series of their publications.
“Two or three examiners come together to go through the thesis in a perfunctory way.
They tick the boxes, everyone is happy, and then a Ph D walks away,” says Jeremy Farrar, director of the biomedical research charity the Wellcome Trust in London.“It almost feels like a rite of passage,” she says.Ph Ds are assessed in very different ways around the world.Her Ph D will be assessed solely on her written thesis, which will be mailed off to examiners and returned with comments.She will do a public presentation of her work later this year, but it won't affect her final result.A lot was at stake: this oral examination would determine whether he passed or failed.“At the one-hour mark someone came in, banged a stick on the floor and said 'hora est',” says Marshall — the ceremonial call that his time was up. I had enjoyed the whole experience far too much, and ended up talking for a few extra minutes.” Marshall's elaborate, public Ph D assessment is very different from that faced by Kelsie Long, an Earth-sciences Ph D candidate at the Australian National University (ANU) in Canberra.“My preference is to assess the researcher,” she says, “but we haven't developed the tools and curriculum to do that.” It's difficult to find figures on how many students fail their Ph D if they get to the point of submitting a thesis but, anecdotally, scientists say that few flunk it outright.More often, students are sent away with minor or major corrections that have to be completed before the Ph D is awarded.That could be because students are analysing more complex questions, performing longer literature reviews and using increasingly complicated methods that require lengthier explanations (see 'The expanding thesis').“It's unnecessary to have such a long thesis,” says Farrar, who recently assessed one such tome.