Matthew Jockers, a University of Nebraska English professor, thinks that there are about six or seven basic plot shapes to any novel.
Jockers came to this conclusion through “microanalysis,” the process of analyzing texts using computers and mapping the shape of the plot in various works of fiction. On his blog he analyzes James Joyce’s Portrait of the Artist as an example to demonstrate his logic and process. Check it out:
In addition to this mathematical approach, I also employed good old subjective evaluation. The tool suggested six or seven, but this number (six, seven) would be rather useless if the resulting shapes did not make any sense to those of us who actually read the books. So, I looked at a lot of plots; everything from two to twenty.
You can check out a video of Jockers’ describing his digital text mining process here. (Via VICE.)