In starting my literature review, I decided a good first step would be to look at some examples – what have others done? what should the final product look like?
Luckily, at UCL there is the brilliant resource of UCL Discovery which is a depository of research (from completed theses to publications and conference papers…etc). It lists EVERY PhD thesis which has been completed from 1919 to 2014. Information provided includes the name of the author, title of their PhD thesis, and in many cases a PDF version of the final document. Brilliant!
Having selected a few theses titles which looked vaguely “public health-y”, I was somewhat surprised with how the authors had approached and presented their literature review sections. The first few I skimmed over had clear references, but there was no explanation as to how they approached their literature review. I wondered whether this information was in the appendices (a flow chart of databases searched, inclusion and exclusion criteria); no such luck. To give an example, one thesis noted:
This section provides a broad overview of the research area investigated in this thesis
If one takes a “broad overview” how do they select the information to be included, and more importantly, how do they decide what information to exclude? Surely this approach is open to bias (which is never a good thing in research).
There are some topics and literature (particularly grey literature) which may be less easily identified through a systematic method – and thus a broad approach is more likely to result in finding relevant information. Secondly, there are those occasions when you are limited by time and space (e.g. a journal publication) where a broad approach of picking the most relevant evidence to your topic makes the most sense.
In my public health training (MPhil in Public Health and 3 years as a registrar) I have learnt that for any topic one should always review the evidence (what do we already know? how credible is the evidence? what is still unknown?) and use a systematic approach. This approach helps me grasp what is currently known on a topic, aids decision making (is the information credible?), and transparent methods allow others to replicate my search to assess/update the review.
My observations from recently published PhD theses suggest that some researchers approach the literature review with less rigour compared to the presentation of the remainder of their thesis – perhaps the literature review is not always perceived to be as important comparative to the other thesis sections (it shouldn’t contain anything original, thats for sure).
There is a word limit and time limit with a PhD, but it is my view that both are flexible enough to accommodate the inclusion of a brief description of methods. Where a systematic approach was taken, then it is important to share your approach – however even if you choose a broad approach (or a mixture of both, which I expect I’m likely to do) a short sentence explaining your approach, and perhaps the limitations of your approach, would be useful to the reader.