Flesch Reading Ease Formula is considered as one of the oldest and most accurate readability formulas. Rudolph Flesch, an author, writing consultant, and a supporter of the Plain English Movement, developed this formula in 1948. Raised in Austria, Rudolph Flesch studied law and earned a Ph.D. in English from the Columbia University. Flesch, through his writings and speeches, advocated a return to phonics. In his article, A New Readability Yardstick, published in the Journal of Applied Psychology in 1948, Flesch proposed the Flesch Reading Ease Readability Formula.
The Flesch Reading Ease Formula is a simple approach to assess the grade-level of the reader. It’s also one of the few accurate measures around that we can rely on without too much scrutiny. This formula is best used on school text. It has since become a standard readability formula used by many US Government Agencies, including the US Department of Defense. However, primarily, we use the formula to assess the difficulty of a reading passage written in English.