The Gunning Fog Index Readability Formula, or simply called FOG Index
, is attributed to American textbook publisher, Robert Gunning
, who was a graduate from Ohio State University. Gunning observed that most high school graduates were unable to read. Much of this reading problem was a writing problem. His opinion was that newspapers and business documents were full of fog and unnecessary complexity.
Gunning realized the problem quite early and became the first to take the new readability research into the workplace. Gunning founded the first consulting firm specializing in readability in 1944. He spent the next few years testing and working with more than 60 large city daily newspapers and popular magazines, helping writers and editors write to their audience.
In 1952, Gunning published a book, The Technique of Clear Writing
and created an easy-to-use Fog Index.