For all his intricate and involved diagramming, Keeler recognized that the core components of a good plot could be summarized simply: interesting, novel, and convincing (as he writes in a 1931 article, “How to Write Book-Length Mystery Stories”). When it comes to gauging a a plot’s interesting-ness, Keeler invites the writer to read his own story while pretending he is an editor, specifically:
Even a tired, cross, worn-out editorial reader who has sworn by the shades of Buddha to discard all the remaining manuscripts of the short-stories and novels in his pile unless they hook him on the very first page, and take the first train to his suburban home. Pretend that - and you’ve set yourself a fortuitous and wholesome standard to write by.
This article is collected in the Harry Stephen Keeler Papers, housed in the RBML.