I have been almost the last four weeks ‘diving’ into my literature & practice review. One thing that I found extremely helpful was to have a previous organisation of authors, subjects and fields, and, at the same time, from different points of view.
As I did a very systematic and well-organised material classification, I realised this approach can be applied as a research method. This research method is also another manner to show how powerful diagrams could be, as they are the main tool used to organise the huge amount of references.
So, the 5-variables method (as I called it) consists in ordering raw material (e.i. references, including books, articles, journals, thesis and websites) following five variables: who, what, when, how and where.
The images below explain each variable.
1) who? Alphabetical order. This first approach is the more common one, and it is usually used to find alphabetically and easily each author.
A-Z order.
2) what? Thematic order (themes, subjects, fields and disciplines). Sometimes, it is not easy to remember the name of the author, but, instead, it is easier to remember his/her specific subject. First of all, it is essential to define general thematic categories related to the research subject, to be aware of all the points of view covered (or that have to be covered). If the research theme is quite complex, it could be also beneficial to define sub-categories from each general category and distinguish them by colour-saturation.
Once I have all references divided into two main groups: literature and practice review references; I define thematic categories directly related to my theme (diagrams): history/context, diagrams/underground, psychology/perception, linguistics/semiology, methodology/research process, graphic/information design, and thesis. I attached a colour to each category.
3) when? Chronological order, following year of publication.
This is a useful approach for historical research, where knowing which period has been covered is key.
Having references chronologically ordered would help to notice if we have many new references, or that we are not taking into account previous authors. In addition, it can be noticed in which periods of time, a theme was most or less discussed.
Timeline. Each box represents an author/book, and it is organised following its year of publication.
4) how? Interdisciplinary order. Design is an interdisciplinary discipline, where many references come from academic disciplines beyond graphics, such as psychology, informatics, cartography, and so on… This approach shows the connections between authors and subjects from different disciplines (usually this approach follows the categories defined for the what variable). In a glance, it can be seen which disciplines are related to each other and which ones are not.
In the image, each box corresponds to one author, its colour matches with a theme, and its saturation indicates where within the theme this author is placed. A box has more than one colour when it is representing a theme related to another (the second colour). The more colours a box has, the more themes it is related to.
5) where? Geographical order (authors’ countries, cities). This is a useful approach for cultural research where, for example, the bias of a theme is crucial.
In this case, the circles are depicting quantity of author from each theme. The smallest circle is representing less than 10 authors for a specific theme that comes from a same country. The medium circle represents 11-15 authors and the biggest more than 15 authors from the same country. Again, this approach follows the categories defined for the what variable.
Of course, this classification can vary as more material is added, but it can be a useful starting point!
Bridging Theory and Practice 
I just came across your site via Twitter. I’ve only starting to read through your posts, but overall, I’m fascinated by the journey you’ve undertaken with your PhD thesis. You’re tackling 2 hefty subjects whose intersection deserves closer study — design process/methods and information design/visualization.
It’s interesting to see your “5-variables” approach to sorting and analyzing your research, as you combine 2 organizing principles:
– the “Five W’s”: who, what, when, where, why, how (You could also add “how much” to indicate quantity; Dan Roam illustrates this principle in “The Back of the Napkin.”)
– Richard Saul Wurman’s LATCH model for organizing information (Location, Alphabet, Time, Category, Hierarchy), described in “Information Anxiety.” The “Five W’s” is a category system which itself contains location (where), time (when).
With that in mind, I would offer some small suggestions on the items above:
1) “Who” is typically organized by alphabetical order in directories, but it is a category of information that can further be organized by location, time, hierarchy, or yet another category.
4) Rather than a “how,” this appears to be another “what” by which to organize research. Each author can be associated with one or several discipline categories, as you’ve indicated. However, the graphic treatment of color banding seems too visually abstract and a bit difficult to read. Perhaps more direct graphic language and less color nuance might help?
Choosing and effectively visualizing organizing principles can be challenging, but the process of discovery pays off. I look forward to seeing your journey unfold.
Michael, many thanks for your comment. Definitely this subject is very interesting! Of course I know about LATCH but I didn’t about Dam Roam. I will read more about him and his 5-Ws. I believe that my 5-variables need more analysis and study, as, at the moment, they are only a stage of my research and not the main objective. My PhD is becoming bigger and bigger and, unfortunately, I won’t be able to include all the information obtain in this journey. However, I am planning to do something else with it!
I apologize if the LATCH reference seemed a bit too elementary. In my work as an information designer, I often find myself coming back to Wurman moreso than Tufte and others in the data visualization or traditional graphic design world. Dan Roam is definitely worth a look from a visual thinking and practical problem solving angle (check out his videos, too).
I see some parallels to my own experience writing and designing an undergrad thesis on information design, so the inevitable snowball effect in the research, writing and design process is familiar. Just remember to stay focused. 😉 Best of luck, Sheila!