Readability - Early Adult Readability Formulas

Early Adult Readability Formulas

During the recession of the 1930s, the U.S. government invested in adult education. In 1931, Douglas Waples and Ralph Tyler published What Adults Want to Read About. It was a two-year study of adult reading interests. Their book showed not only what people read but what they would like to read. They found that many readers lacked suitable reading materials: they would have liked to learn but the reading materials were too hard for them.

Lyman Bryson of Teachers College, Columbia University found that many adults had poor reading ability due to poor education. Even though colleges had long taught writing in a clear and readable style, Bryson found that it was very rare. He wrote that such language is the result of a "discipline and artistry that few people who have ideas will take the trouble to achieve... If simple language were easy, many of our problems would have been solved long ago." Bryson helped set up the Readability Laboratory at the College. Two of his students were Irving Lorge and Rudolf Flesch.

In 1934, Ralph Ojemann investigated the reading skills of adults, the factors which most directly affect reading ease, and the causes of each level of difficulty. He did not invent a formula but a method for assessing the difficulty of materials for parent education. He was the first to assess the validity of this method by using 16 magazine passages that had been tested on actual readers. He evaluated 14 measurable and three reported factors affecting reading ease.

Ojemann put great emphasis on the reported features, such as whether the text was coherent or unduly abstract. He used his 16 passages to compare and judge the reading ease of other texts, a method known today as scaling. He showed that even though these factors cannot be measured, they cannot be ignored.

That same year, Ralph Tyler and Edgar Dale published the first adult reading ease formula which was based on passages from adult magazines. Of the 29 factors that had been significant for young readers, they found ten that were significant for adults. Three of them they used in their formula.

In 1935, William S. Gray of the University of Chicago and Bernice Leary of Xavier College in Chicago published What Makes a Book Readable, one of the most important books in readability research. Like Dale and Tyler, they focused on what makes books readable for adults of limited reading ability.

The book included the first scientific study of the reading skills of adults in the U.S. The sample included 1,690 adults from a variety of settings and areas of the U.S. The test used a number of passages from newspapers, magazines, and books as well as a standard reading test. They found a mean grade score of 7.81 (eighth month of the seventh grade). About one-third read at the 2nd to 6th-grade level, one-third at the 7th to 12th-grade level, and one-third at the 13th to 17th grade level.

The authors emphasized that one-half of the adult population are lacking suitable reading materials. They wrote, "For them, the enriching values of reading are denied unless materials reflecting adult interests are adapted to their needs." The poorest readers, one-sixth of the adult population, need "simpler materials for use in promoting functioning literacy and in establishing fundamental reading habits."

Gray and Leary then analyzed 228 variables that affect reading ease and divided them into four types: 1. content, 2. style, 3. format, and organization. They found that content was most important, followed closely by style. Third was format, followed closely by organization. They found no way to measure content, format, or organization, but they could measure variables of style. Among the 17 significant measurable variables of style, they selected five to create a formula: 1. average sentence length, 2 number of different hard words, 3. number of personal pronouns, percentage of unique words, and number of prepositional phrases. Their formula had a correlation of .645 with comprehension as measured by reading tests given to about 800 adults.

In 1939, Irving Lorge published an article showing that there were other combinations of variables which were more accurate signs of difficulty than the ones used by Gray and Leary. His research also showed that "the vocabulary load is the most important concomitant of difficulty. In 1944, Lorge published his Lorge Index, a readability formula using three variables, setting the stage for the simpler and more reliable formulas that would follow.

By 1940, investigators had:

• Successfully used statistical methods to analyze the reading ease of texts.
• Found that unusual words and sentence length were among the first causes of reading difficulty.
• Used vocabulary and sentence length in formulas to predict the reading ease of a text.