Typography
Information about the effectiveness of typography and design. Some of this comes from formal 'scientific' experiments, but most comes from commercial sources. Naturally, sales results before and after a book or magazine redesign are compared. A redesign of the typography on the jacket of a book (Roget's Thesaurus) "nearly doubled the sales". Typographers themselves carry out mini-experiments to test alternatives. This is an extension of scientific method to what is, at heart, an artistic process.