Is a tree/graph visualization of methods literature a useful addition to lit review? My PhD proposal includes a short lit review (3-4 pages).
Some of the finest Proposal lit review examples I have been given have made good use of tables and plots to summarize the development of methods in the area over time.
I can not produce a plot showing how various methods clearly improve on the last, as each new method in my subfield used as different evaluation method or is for a slightly different task (Though If I really wanted, most do evaluate old methods on their new task).
I already have a large table, describing the methods, which paper they are from and what their evaluation method was.
I was thinking I could construct a Tree for which methods spawned which other methods. Technically a graph, since some methods
Something along the lines of:

This could be enhanced with numbered references to the papers in my reference list wich define the models, and which line up with the table giving more detail. It could also perhaps have years added if I wanted to show how the field developed overtime. (and could be made more complete)
I'm not certain how useful showing this relationship between methods is though.
Just looking at that chart which I put together in 5 minutes to ask this question does fill me with some satisfaction. That chart (were it correct, and enhanced with paper links) basically shows the development of my field up to its roots.
Is something like this worth having in a lit review?
It would take &lt;1/2 page.  and fixing it up in TIKZ would prob take a few hours.
My research is about proposing new methods,
thus when complete it would fit somewhere in the tree. (Near the bottom since it would be building on a lot of work).
So I think it would be valuable.
However I have never seen a chart like this anywhere before.
I'm a little bit cautious about diagrams like this. The reason is that often the relationship between different pieces of work is much more messy and partial than is readily captured by such a diagram, and systematizing onto a diagram can cause one to unintentionally leave out or "neaten up" some of the most interesting pieces of hybrid work.

That said, sometimes diagrams are appropriate---consider, for example, some of the wonderful diagrams for relationships between computational complexity classes.  In this case, a diagram is a wonderful aid to comprehension, and as such, if the work in your field really does organize so nicely, I think that using a diagram is a good use of space, particularly in a document like a thesis or thesis proposal where you are not facing tight space constraints.