There has been some discussion on the Logos blog as well as on the ESV blog about comparing graphing the density of quotations of the Old Testament in the New Testament. It’s interesting to see a comment on a blog turn into useful data.
I’ve been thinking about another way of representing similar data graphically. What if instead of a bar graph, there was an x/y axis with each verse of the OT (or a particular OT book) assigned to the x-axis and each verse of the NT (or NT book) assigned to the y-axis. When a NT writer quotes from a particular verse of the OT there would be a point plotted at the intersection of the two. Thus a “cluster” of quotes could be seen. Perhaps a z-axis could be added that would cover verbal affinities (e.g. if it is a quotation, how many words are quoted verbatim; if it is an allusion how many similar words or roots; if its an echo, how loud?).
Sometimes charts can be nothing more than “bells and whistles,” but I think that plotting information like this would be helpful as well. The example I have shown above is a mock graph of Isaiah 40:6-8 in 1 Peter 1:24-25. The z-axis does not necessarily represent anything, but it illustrates potential. Different colors could be used as well, perhaps in some form of grey-scale to represent quotes, allusions and echoes (or some other user/editor defined system of evaluating the “saturation” of the quote).